Use pm_runtime_(get|put)_sync to control the bridge power, and add
SET_SYSTEM_SLEEP_PM_OPS with pm_runtime_force_(suspend|resume) to it6505
driver. Without SET_SYSTEM_SLEEP_PM_OPS, the bridge will be powered on
unnecessarily when no external display is connected.

Fixes: b5c84a9e ("drm/bridge: add it6505 driver")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221004044943.2407781-2-treapking@chromium.org

Add spi_device_id entries to silent following SPI warning:

SPI driver ws2401-panel has no spi_device_id for samsung,lms380kf01
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220915163437.2519754-1-weiyongjun@huaweicloud.com

Add spi_device_id entries to silent following SPI warning:

SPI driver tpo-tpg110-panel has no spi_device_id for tpo,tpg110
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220915163431.2519736-1-weiyongjun@huaweicloud.com

Add spi_device_id entries to silent following SPI warning:

SPI driver db7430-panel has no spi_device_id for samsung,lms397kf04
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220915163156.2519577-1-weiyongjun@huaweicloud.com

When many entities are competing for the same run queue
on the same scheduler, we observe an unusually long wait
times and some jobs get starved. This has been observed on GPUVis.

The issue is due to the Round Robin policy used by schedulers
to pick up the next entity's job queue for execution. Under stress
of many entities and long job queues within entity some
jobs could be stuck for very long time in it's entity's
queue before being popped from the queue and executed
while for other entities with smaller job queues a job
might execute earlier even though that job arrived later
then the job in the long queue.

Fix:
Add FIFO selection policy to entities in run queue, chose next entity
on run queue in such order that if job on one entity arrived
earlier then job on another entity the first job will start
executing earlier regardless of the length of the entity's job
queue.

v2:
Switch to rb tree structure for entities based on TS of
oldest job waiting in the job queue of an entity. Improves next
entity extraction to O(1). Entity TS update
O(log N) where N is the number of entities in the run-queue

Drop default option in module control parameter.

v3:
Various cosmetical fixes and minor refactoring of fifo update function. (Luben)

v4:
Switch drm_sched_rq_select_entity_fifo to in order search (Luben)

v5: Fix up drm_sched_rq_select_entity_fifo loop (Luben)

v6: Add missing drm_sched_rq_remove_fifo_locked

v7: Fix ts sampling bug and more cosmetic stuff (Luben)

v8: Fix module parameter string (Luben)

Cc: Luben Tuikov <luben.tuikov@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Direct Rendering Infrastructure - Development <dri-devel@lists.freedesktop.org>
Cc: AMD Graphics <amd-gfx@lists.freedesktop.org>
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Tested-by: Yunxiang Li (Teddy) <Yunxiang.Li@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220930041258.1050247-1-luben.tuikov@amd.com

In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-3-yuancan@huawei.com

In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-2-yuancan@huawei.com
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-2-yuancan@huawei.com

Add Multi-Inno Technology MI0800FT-9 8" 800x600 DPI panel support.
Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
To: dri-devel@lists.freedesktop.org
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220812114832.4946-1-cniedermaier@dh-electronics.com

Add Multi-Inno Technology MI0800FT-9 8" 800x600 DPI panel
compatible string.
Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: devicetree@vger.kernel.org
To: dri-devel@lists.freedesktop.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220812114600.4895-1-cniedermaier@dh-electronics.com

Correct I2C address for the register list in lt8912_write_lvds_config(),
these registers are on the first I2C address (0x48), the current
function is just writing garbage to the wrong registers and this creates
multiple issues (artifacts and output completely corrupted) on some HDMI
displays.

Correct I2C address comes from Lontium documentation and it is the one
used on other out-of-tree LT8912B drivers [1].

[1] https://github.com/boundarydevices/linux/blob/boundary-imx_5.10.x_2.0.0/drivers/video/lt8912.c#L296

Fixes: 30e2ae94 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-4-dev@pschenker.ch
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-5-dev@pschenker.ch

The Lontium LT8912 does have a setting for DVI or HDMI. This patch reads
from EDID what the display needs and sets it accordingly.

Fixes: 30e2ae94 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-3-dev@pschenker.ch

Currently the bridge driver does not take care whether or not the display
needs positive/negative vertical/horizontal syncs. Pass these two flags
to the bridge from the EDID that was read out from the display.

Fixes: 30e2ae94 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-2-dev@pschenker.ch

The sequence for Source DP PHY CTS automation is [2][1]:
1- Emulate successful Link Training(LT)
2- Short HPD and change link rates and number of lanes by LT.
(This is same flow for Link Layer CTS)
3- Short HPD and change PHY test pattern and swing/pre-emphasis
levels (This step should not trigger LT)

The problem is with DP PHY compliance setup as follow:

     [DPTX + on board LTTPR]------Main Link--->[Scope]
     	     	        ^                         |
			|                         |
			|                         |
			----------Aux Ch------>[Aux Emulator]

At step 3, before writing TRAINING_LANEx_SET/LINK_QUAL_PATTERN_SET
to declare the pattern/swing requested by scope, we write link
config in LINK_BW_SET/LANE_COUNT_SET on a port that has LTTPR.
As LTTPR snoops aux transaction, LINK_BW_SET/LANE_COUNT_SET writes
indicate a LT will start [Check DP 2.0 E11 -Sec 3.6.8.2 & 3.6.8.6.3],
and LTTPR will reset the link and stop sending DP signals to
DPTX/Scope causing the measurements to fail. Note that step 3 will
not trigger LT and DP link will never recovered by the
Aux Emulator/Scope.

The reset of link can be tested with a monitor connected to LTTPR
port simply by writing to LINK_BW_SET or LANE_COUNT_SET as follow

  igt/tools/dpcd_reg write --offset=0x100 --value 0x14 --device=2

OR

  printf '\x14' | sudo dd of=/dev/drm_dp_aux2 bs=1 count=1 conv=notrunc
  seek=$((0x100))

This single aux write causes the screen to blank, sending short HPD to
DPTX, setting LINK_STATUS_UPDATE = 1 in DPCD 0x204, and triggering LT.

As stated in [1]:
"Before any TX electrical testing can be performed, the link between a
DPTX and DPRX (in this case, a piece of test equipment), including all
LTTPRs within the path, shall be trained as defined in this Standard."

In addition, changing Phy pattern/Swing/Pre-emphasis (Step 3) uses the
same link rate and lane count applied on step 2, so no need to redo LT.

The fix is to not rewrite link config in step 3, and just writes
TRAINING_LANEx_SET and LINK_QUAL_PATTERN_SET

[1]: DP 2.0 E11 - 3.6.11.1 LTTPR DPTX_PHY Electrical Compliance

[2]: Configuring UnigrafDPTC Controller - Automation Test Sequence
https://www.keysight.com/us/en/assets/9922-01244/help-files/
D9040DPPC-DisplayPort-Test-Software-Online-Help-latest.chm

Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Or Cochvi <or.cochvi@intel.com>
Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220916054900.415804-1-khaled.almahallawy@intel.com

Replace DRM_DEBUG_KMS() with drm_dbg_kms() which allows specifying
the DRM device to provide more context.
Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905103559.118561-1-contact@emersion.fr

Extend the existing test cases to test the conversion from XRGB8888 to
grayscale.
Tested-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: David Gow <davidgow@google.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926080837.65734-4-jose.exposito89@gmail.com

Extend the existing test cases to test the conversion from XRGB8888 to
XRGB2101010.

In order to be able to call drm_fb_xrgb8888_to_xrgb2101010() when
compiling CONFIG_DRM_KMS_HELPER as a module export the symbol.
Tested-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: David Gow <davidgow@google.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926080837.65734-3-jose.exposito89@gmail.com

Extend the existing test cases to test the conversion from XRGB8888 to
RGB888.
Tested-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: David Gow <davidgow@google.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926080837.65734-2-jose.exposito89@gmail.com

Add support for the BOE - NT116WHM-N4C (HW: V8.1) panel.
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220927063524.493591-1-sean.hong@quanta.corp-partner.google.com

This panel has the same delay timing as N116BCA-EA1. So, fix the
delay timing from delay_200_500_p2e80 to delay_200_500_e80_d50.

Fixes: c7bcc105 ("drm/panel-edp: Add INX N116BCA-EA2")
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220927021835.488803-1-sean.hong@quanta.corp-partner.google.com

This panel has the same delay timing as N116BCA-EA1. So, fix the
delay timing from delay_200_500_p2e80 to delay_200_500_e80_d50.

Fixes: 9f4a5714 ("drm/panel-edp: Add INX N116BCN-EA1")
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220927021021.488295-1-sean.hong@quanta.corp-partner.google.com

Synchronize CPU access to GEM BOs with other drivers when updating the
screen buffer. Imported DMA buffers might otherwise contain stale data.
Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220927095249.1919385-1-javierm@redhat.com

The struct drm_plane .state shouldn't be accessed directly but instead the
drm_atomic_get_new_plane_state() helper function should be used.

This is based on a similar patch from Thomas Zimmermann for the simpledrm
driver. No functional changes.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923083447.1679780-1-javierm@redhat.com

Synchronize CPU access to GEM BOs with other drivers when updating the
screen buffer. Imported buffers might otherwise contain stale data.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922130944.27138-6-tzimmermann@suse.de

Iterate over all damage clips and updated them one by one. Replaces
the merging of damage areas, which can result in significant overhead
if damage areas are not close to each other.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922130944.27138-5-tzimmermann@suse.de

The primary plane implements atomic_disable, so atomic_update will
not be called without a framebuffer set. Remove the test for !fb.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922130944.27138-4-tzimmermann@suse.de

Lookup the plane's state in atomic_update with the helper
drm_atomic_get_new_plane_state(). Also rename the helpers'
state arguments. No functional changes.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922130944.27138-3-tzimmermann@suse.de

If not given, compute the stride with drm_format_info_min_pitch(). It's
the standard helper for this purpose.
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Fixes: fd9e3169 ("drm/simpledrm: Compute framebuffer stride if not set")
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20220922130944.27138-2-tzimmermann@suse.de

Add support for the INX - N116BCA-EA2 (HW: C1) panel
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926100839.482804-1-sean.hong@quanta.corp-partner.google.com

Let's make sure nobody is calling those functions without holding the
appropriate locks.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220715111533.467012-2-christian.koenig@amd.com

The symbol is not used outside of the file, so mark it static.

Fixes the following warning:

drivers/gpu/drm/ast/ast_drv.c:42:5: warning: symbol 'ast_modeset'
was not declared. Should it be static?
Signed-off-by: ruanjinjie <ruanjinjie@huawei.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220926023253.739699-1-ruanjinjie@huawei.com

Add support for the AUO - B116XAK01.6 (HW: 1A) panel.
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923055133.302740-1-sean.hong@quanta.corp-partner.google.com

Add support for the BOE - NT116WHM-N21 (HW: V8.2) panel.
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923054614.302440-1-sean.hong@quanta.corp-partner.google.com

Add support for the BOE - NT116WHM-N21 (HW: V8.1) panel.
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923085028.306790-1-sean.hong@quanta.corp-partner.google.com

Add support for the INX - N116BCN-EA1 (HW: C4) panel.
Signed-off-by: Sean Hong <sean.hong@quanta.corp-partner.google.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923053729.301626-1-sean.hong@quanta.corp-partner.google.com

The ->ring_idx_mask variable is a u64 so static checkers, Smatch in
this case, complain if the BIT() is not also a u64.

drivers/gpu/drm/virtio/virtgpu_ioctl.c:50 virtio_gpu_fence_event_create()
warn: should '(1 << ring_idx)' be a 64 bit type?

Fixes: cd7f5ca3 ("drm/virtio: implement context init: add virtio_gpu_fence_event")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/YygN7jY0GdUSQSy0@kiliSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

Since qxl_io_reset(qdev) will be called immediately
after qxl_ring_create() been called,
and parameter like notify_on_prod will be set to default value.
So the call to qxl_ring_init_hdr() before becomes meaningless.

Signed-off-by: Zongmin Zhou<zhouzongmin@kylinos.cn>
Suggested-by: Ming Xie<xieming@kylinos.cn>
Link: http://patchwork.freedesktop.org/patch/msgid/20220920065023.1633303-1-zhouzongmin@kylinos.cnSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init
were not manually removed at module unload time, which caused dangling
references to freed memory to remain linked in the global bridge_list.

When loading the driver modules back in, the same functions would again
call drm_bridge_add, and when traversing the global bridge_list, would
end up peeking into freed memory.

Once again KASAN revealed the problem:

[  +0.000095] =============================================================
[  +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120
[  +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483

[  +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1
[  +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)
[  +0.000008] Call trace:
[  +0.000006]  dump_backtrace+0x1ec/0x280
[  +0.000012]  show_stack+0x24/0x80
[  +0.000008]  dump_stack_lvl+0x98/0xd4
[  +0.000011]  print_address_description.constprop.0+0x80/0x520
[  +0.000011]  print_report+0x128/0x260
[  +0.000008]  kasan_report+0xb8/0xfc
[  +0.000008]  __asan_report_load8_noabort+0x3c/0x50
[  +0.000009]  __list_add_valid+0x9c/0x120
[  +0.000009]  drm_bridge_add+0x6c/0x104 [drm]
[  +0.000165]  dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]
[  +0.000022]  meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]
[  +0.000014]  component_bind+0x174/0x520
[  +0.000012]  component_bind_all+0x1a8/0x38c
[  +0.000010]  meson_drv_bind_master+0x5e8/0xb74 [meson_drm]
[  +0.000032]  meson_drv_bind+0x20/0x2c [meson_drm]
[  +0.000027]  try_to_bring_up_aggregate_device+0x19c/0x390
[  +0.000010]  component_master_add_with_match+0x1c8/0x284
[  +0.000009]  meson_drv_probe+0x274/0x280 [meson_drm]
[  +0.000026]  platform_probe+0xd0/0x220
[  +0.000009]  really_probe+0x3ac/0xa80
[  +0.000009]  __driver_probe_device+0x1f8/0x400
[  +0.000009]  driver_probe_device+0x68/0x1b0
[  +0.000009]  __driver_attach+0x20c/0x480
[  +0.000008]  bus_for_each_dev+0x114/0x1b0
[  +0.000009]  driver_attach+0x48/0x64
[  +0.000008]  bus_add_driver+0x390/0x564
[  +0.000009]  driver_register+0x1a8/0x3e4
[  +0.000009]  __platform_driver_register+0x6c/0x94
[  +0.000008]  meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]
[  +0.000027]  do_one_initcall+0xc4/0x2b0
[  +0.000011]  do_init_module+0x154/0x570
[  +0.000011]  load_module+0x1a78/0x1ea4
[  +0.000008]  __do_sys_init_module+0x184/0x1cc
[  +0.000009]  __arm64_sys_init_module+0x78/0xb0
[  +0.000009]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000012]  el0t_64_sync_handler+0x11c/0x150
[  +0.000008]  el0t_64_sync+0x18c/0x190

[  +0.000016] Allocated by task 879:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000011]  __kasan_kmalloc+0x90/0xd0
[  +0.000007]  __kmalloc+0x278/0x4a0
[  +0.000011]  mpi_resize+0x13c/0x1d0
[  +0.000011]  mpi_powm+0xd24/0x1570
[  +0.000009]  rsa_enc+0x1a4/0x30c
[  +0.000009]  pkcs1pad_verify+0x3f0/0x580
[  +0.000009]  public_key_verify_signature+0x7a8/0xba4
[  +0.000010]  public_key_verify_signature_2+0x40/0x60
[  +0.000008]  verify_signature+0xb4/0x114
[  +0.000008]  pkcs7_validate_trust_one.constprop.0+0x3b8/0x574
[  +0.000009]  pkcs7_validate_trust+0xb8/0x15c
[  +0.000008]  verify_pkcs7_message_sig+0xec/0x1b0
[  +0.000012]  verify_pkcs7_signature+0x78/0xac
[  +0.000007]  mod_verify_sig+0x110/0x190
[  +0.000009]  module_sig_check+0x114/0x1e0
[  +0.000009]  load_module+0xa0/0x1ea4
[  +0.000008]  __do_sys_init_module+0x184/0x1cc
[  +0.000008]  __arm64_sys_init_module+0x78/0xb0
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0x1a8/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000009]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000013] Freed by task 2422:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000009]  kasan_set_track+0x2c/0x40
[  +0.000007]  kasan_set_free_info+0x28/0x50
[  +0.000009]  ____kasan_slab_free+0x128/0x1d4
[  +0.000008]  __kasan_slab_free+0x18/0x24
[  +0.000007]  slab_free_freelist_hook+0x108/0x230
[  +0.000010]  kfree+0x110/0x35c
[  +0.000008]  release_nodes+0xf0/0x16c
[  +0.000009]  devres_release_group+0x180/0x270
[  +0.000008]  take_down_aggregate_device+0xcc/0x160
[  +0.000010]  component_del+0x18c/0x360
[  +0.000009]  meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[  +0.000013]  platform_remove+0x64/0xb0
[  +0.000008]  device_remove+0xb8/0x154
[  +0.000009]  device_release_driver_internal+0x398/0x5b0
[  +0.000009]  driver_detach+0xac/0x1b0
[  +0.000009]  bus_remove_driver+0x158/0x29c
[  +0.000008]  driver_unregister+0x70/0xb0
[  +0.000009]  platform_driver_unregister+0x20/0x2c
[  +0.000007]  meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[  +0.000012]  __do_sys_delete_module+0x288/0x400
[  +0.000009]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000009]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000008]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000013] The buggy address belongs to the object at ffff00003da29000
               which belongs to the cache kmalloc-1k of size 1024
[  +0.000008] The buggy address is located 496 bytes inside of
               1024-byte region [ffff00003da29000, ffff00003da29400)

[  +0.000015] The buggy address belongs to the physical page:
[  +0.000009] page:fffffc0000f68a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3da28
[  +0.000012] head:fffffc0000f68a00 order:3 compound_mapcount:0 compound_pincount:0
[  +0.000009] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
[  +0.000019] raw: 0ffff00000010200 fffffc0000eb5c08 fffffc0000d96608 ffff000000002a80
[  +0.000008] raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000
[  +0.000008] page dumped because: kasan: bad access detected

[  +0.000011] Memory state around the buggy address:
[  +0.000009]  ffff00003da29080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]  ffff00003da29100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007] >ffff00003da29180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]                                                              ^
[  +0.000008]  ffff00003da29200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000006]  ffff00003da29280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007] ==================================================================

Fix by keeping track of which encoders were initialised in the meson_drm
structure and manually removing their bridges at aggregate driver's unbind
time.
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220920222842.1053234-1-adrian.larumbe@collabora.com

Because component_master_del wasn't being called when unloading the
meson_drm module, the aggregate device would linger forever in the global
aggregate_devices list. That means when unloading and reloading the
meson_dw_hdmi module, component_add would call into
try_to_bring_up_aggregate_device and find the unbound meson_drm aggregate
device.

This would in turn dereference some of the aggregate_device's struct
entries which point to memory automatically freed by the devres API when
unbinding the aggregate device from meson_drv_unbind, and trigger an
use-after-free bug:

[  +0.000014] =============================================================
[  +0.000007] BUG: KASAN: use-after-free in find_components+0x468/0x500
[  +0.000017] Read of size 8 at addr ffff000006731688 by task modprobe/2536
[  +0.000018] CPU: 4 PID: 2536 Comm: modprobe Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1
[  +0.000010] Hardware name: Hardkernel ODROID-N2Plus (DT)
[  +0.000008] Call trace:
[  +0.000005]  dump_backtrace+0x1ec/0x280
[  +0.000011]  show_stack+0x24/0x80
[  +0.000007]  dump_stack_lvl+0x98/0xd4
[  +0.000010]  print_address_description.constprop.0+0x80/0x520
[  +0.000011]  print_report+0x128/0x260
[  +0.000007]  kasan_report+0xb8/0xfc
[  +0.000007]  __asan_report_load8_noabort+0x3c/0x50
[  +0.000009]  find_components+0x468/0x500
[  +0.000008]  try_to_bring_up_aggregate_device+0x64/0x390
[  +0.000009]  __component_add+0x1dc/0x49c
[  +0.000009]  component_add+0x20/0x30
[  +0.000008]  meson_dw_hdmi_probe+0x28/0x34 [meson_dw_hdmi]
[  +0.000013]  platform_probe+0xd0/0x220
[  +0.000008]  really_probe+0x3ac/0xa80
[  +0.000008]  __driver_probe_device+0x1f8/0x400
[  +0.000008]  driver_probe_device+0x68/0x1b0
[  +0.000008]  __driver_attach+0x20c/0x480
[  +0.000009]  bus_for_each_dev+0x114/0x1b0
[  +0.000007]  driver_attach+0x48/0x64
[  +0.000009]  bus_add_driver+0x390/0x564
[  +0.000007]  driver_register+0x1a8/0x3e4
[  +0.000009]  __platform_driver_register+0x6c/0x94
[  +0.000007]  meson_dw_hdmi_platform_driver_init+0x30/0x1000 [meson_dw_hdmi]
[  +0.000014]  do_one_initcall+0xc4/0x2b0
[  +0.000008]  do_init_module+0x154/0x570
[  +0.000010]  load_module+0x1a78/0x1ea4
[  +0.000008]  __do_sys_init_module+0x184/0x1cc
[  +0.000008]  __arm64_sys_init_module+0x78/0xb0
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000009]  do_el0_svc+0x50/0x70
[  +0.000008]  el0_svc+0x68/0x1a0
[  +0.000009]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000014] Allocated by task 902:
[  +0.000007]  kasan_save_stack+0x2c/0x5c
[  +0.000009]  __kasan_kmalloc+0x90/0xd0
[  +0.000007]  __kmalloc_node+0x240/0x580
[  +0.000010]  memcg_alloc_slab_cgroups+0xa4/0x1ac
[  +0.000010]  memcg_slab_post_alloc_hook+0xbc/0x4c0
[  +0.000008]  kmem_cache_alloc_node+0x1d0/0x490
[  +0.000009]  __alloc_skb+0x1d4/0x310
[  +0.000010]  alloc_skb_with_frags+0x8c/0x620
[  +0.000008]  sock_alloc_send_pskb+0x5ac/0x6d0
[  +0.000010]  unix_dgram_sendmsg+0x2e0/0x12f0
[  +0.000010]  sock_sendmsg+0xcc/0x110
[  +0.000007]  sock_write_iter+0x1d0/0x304
[  +0.000008]  new_sync_write+0x364/0x460
[  +0.000007]  vfs_write+0x420/0x5ac
[  +0.000008]  ksys_write+0x19c/0x1f0
[  +0.000008]  __arm64_sys_write+0x78/0xb0
[  +0.000007]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0x1a8/0x260
[  +0.000009]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000008]  el0t_64_sync_handler+0x11c/0x150
[  +0.000008]  el0t_64_sync+0x18c/0x190

[  +0.000013] Freed by task 2509:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000007]  kasan_set_track+0x2c/0x40
[  +0.000008]  kasan_set_free_info+0x28/0x50
[  +0.000008]  ____kasan_slab_free+0x128/0x1d4
[  +0.000008]  __kasan_slab_free+0x18/0x24
[  +0.000007]  slab_free_freelist_hook+0x108/0x230
[  +0.000010]  kfree+0x110/0x35c
[  +0.000008]  release_nodes+0xf0/0x16c
[  +0.000008]  devres_release_all+0xfc/0x180
[  +0.000008]  device_unbind_cleanup+0x24/0x164
[  +0.000008]  device_release_driver_internal+0x3e8/0x5b0
[  +0.000010]  driver_detach+0xac/0x1b0
[  +0.000008]  bus_remove_driver+0x158/0x29c
[  +0.000008]  driver_unregister+0x70/0xb0
[  +0.000009]  platform_driver_unregister+0x20/0x2c
[  +0.000007]  0xffff800003722d98
[  +0.000012]  __do_sys_delete_module+0x288/0x400
[  +0.000009]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000008]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000013] Last potentially related work creation:
[  +0.000007]  kasan_save_stack+0x2c/0x5c
[  +0.000007]  __kasan_record_aux_stack+0xb8/0xf0
[  +0.000009]  kasan_record_aux_stack_noalloc+0x14/0x20
[  +0.000008]  insert_work+0x54/0x290
[  +0.000009]  __queue_work+0x48c/0xd24
[  +0.000008]  queue_work_on+0x90/0x11c
[  +0.000008]  call_usermodehelper_exec+0x188/0x404
[  +0.000010]  kobject_uevent_env+0x5a8/0x794
[  +0.000010]  kobject_uevent+0x14/0x20
[  +0.000008]  driver_register+0x230/0x3e4
[  +0.000009]  __platform_driver_register+0x6c/0x94
[  +0.000007]  gxbb_driver_init+0x28/0x34
[  +0.000010]  do_one_initcall+0xc4/0x2b0
[  +0.000008]  do_initcalls+0x20c/0x24c
[  +0.000010]  kernel_init_freeable+0x22c/0x278
[  +0.000009]  kernel_init+0x3c/0x170
[  +0.000008]  ret_from_fork+0x10/0x20

[  +0.000013] The buggy address belongs to the object at ffff000006731600
               which belongs to the cache kmalloc-256 of size 256
[  +0.000009] The buggy address is located 136 bytes inside of
               256-byte region [ffff000006731600, ffff000006731700)

[  +0.000015] The buggy address belongs to the physical page:
[  +0.000008] page:fffffc000019cc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff000006730a00 pfn:0x6730
[  +0.000011] head:fffffc000019cc00 order:2 compound_mapcount:0 compound_pincount:0
[  +0.000008] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
[  +0.000016] raw: 0ffff00000010200 fffffc00000c3d08 fffffc0000ef2b08 ffff000000002680
[  +0.000009] raw: ffff000006730a00 0000000000150014 00000001ffffffff 0000000000000000
[  +0.000006] page dumped because: kasan: bad access detected

[  +0.000011] Memory state around the buggy address:
[  +0.000007]  ffff000006731580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  +0.000007]  ffff000006731600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007] >ffff000006731680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]                       ^
[  +0.000006]  ffff000006731700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  +0.000007]  ffff000006731780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  +0.000006] ==================================================================

Fix by adding 'remove' driver callback for meson-drm, and explicitly deleting the
aggregate device.
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220919010940.419893-3-adrian.larumbe@collabora.com

Unloading the driver triggers the following KASAN warning:

[  +0.006275] =============================================================
[  +0.000029] BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0x1a0
[  +0.000026] Read of size 8 at addr ffff000020c395e0 by task rmmod/2695

[  +0.000019] CPU: 5 PID: 2695 Comm: rmmod Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1
[  +0.000013] Hardware name: Hardkernel ODROID-N2Plus (DT)
[  +0.000008] Call trace:
[  +0.000007]  dump_backtrace+0x1ec/0x280
[  +0.000013]  show_stack+0x24/0x80
[  +0.000008]  dump_stack_lvl+0x98/0xd4
[  +0.000011]  print_address_description.constprop.0+0x80/0x520
[  +0.000011]  print_report+0x128/0x260
[  +0.000007]  kasan_report+0xb8/0xfc
[  +0.000008]  __asan_report_load8_noabort+0x3c/0x50
[  +0.000010]  __list_del_entry_valid+0xe0/0x1a0
[  +0.000009]  drm_atomic_private_obj_fini+0x30/0x200 [drm]
[  +0.000172]  drm_bridge_detach+0x94/0x260 [drm]
[  +0.000145]  drm_encoder_cleanup+0xa4/0x290 [drm]
[  +0.000144]  drm_mode_config_cleanup+0x118/0x740 [drm]
[  +0.000143]  drm_mode_config_init_release+0x1c/0x2c [drm]
[  +0.000144]  drm_managed_release+0x170/0x414 [drm]
[  +0.000142]  drm_dev_put.part.0+0xc0/0x124 [drm]
[  +0.000143]  drm_dev_put+0x20/0x30 [drm]
[  +0.000142]  meson_drv_unbind+0x1d8/0x2ac [meson_drm]
[  +0.000028]  take_down_aggregate_device+0xb0/0x160
[  +0.000016]  component_del+0x18c/0x360
[  +0.000009]  meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[  +0.000015]  platform_remove+0x64/0xb0
[  +0.000009]  device_remove+0xb8/0x154
[  +0.000009]  device_release_driver_internal+0x398/0x5b0
[  +0.000009]  driver_detach+0xac/0x1b0
[  +0.000009]  bus_remove_driver+0x158/0x29c
[  +0.000009]  driver_unregister+0x70/0xb0
[  +0.000008]  platform_driver_unregister+0x20/0x2c
[  +0.000008]  meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[  +0.000012]  __do_sys_delete_module+0x288/0x400
[  +0.000011]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000009]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000009]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000012]  el0t_64_sync_handler+0x11c/0x150
[  +0.000008]  el0t_64_sync+0x18c/0x190

[  +0.000018] Allocated by task 0:
[  +0.000007] (stack is not available)

[  +0.000011] Freed by task 2695:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000011]  kasan_set_track+0x2c/0x40
[  +0.000008]  kasan_set_free_info+0x28/0x50
[  +0.000009]  ____kasan_slab_free+0x128/0x1d4
[  +0.000008]  __kasan_slab_free+0x18/0x24
[  +0.000007]  slab_free_freelist_hook+0x108/0x230
[  +0.000011]  kfree+0x110/0x35c
[  +0.000008]  release_nodes+0xf0/0x16c
[  +0.000009]  devres_release_group+0x180/0x270
[  +0.000008]  component_unbind+0x128/0x1e0
[  +0.000010]  component_unbind_all+0x1b8/0x264
[  +0.000009]  meson_drv_unbind+0x1a0/0x2ac [meson_drm]
[  +0.000025]  take_down_aggregate_device+0xb0/0x160
[  +0.000009]  component_del+0x18c/0x360
[  +0.000009]  meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[  +0.000012]  platform_remove+0x64/0xb0
[  +0.000008]  device_remove+0xb8/0x154
[  +0.000009]  device_release_driver_internal+0x398/0x5b0
[  +0.000009]  driver_detach+0xac/0x1b0
[  +0.000009]  bus_remove_driver+0x158/0x29c
[  +0.000008]  driver_unregister+0x70/0xb0
[  +0.000008]  platform_driver_unregister+0x20/0x2c
[  +0.000008]  meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[  +0.000011]  __do_sys_delete_module+0x288/0x400
[  +0.000010]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000009]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000014] The buggy address belongs to the object at ffff000020c39000
               which belongs to the cache kmalloc-4k of size 4096
[  +0.000008] The buggy address is located 1504 bytes inside of
               4096-byte region [ffff000020c39000, ffff000020c3a000)

[  +0.000016] The buggy address belongs to the physical page:
[  +0.000009] page:fffffc0000830e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20c38
[  +0.000013] head:fffffc0000830e00 order:3 compound_mapcount:0 compound_pincount:0
[  +0.000008] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
[  +0.000019] raw: 0ffff00000010200 fffffc0000fd4808 fffffc0000126208 ffff000000002e80
[  +0.000009] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
[  +0.000008] page dumped because: kasan: bad access detected

[  +0.000011] Memory state around the buggy address:
[  +0.000008]  ffff000020c39480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]  ffff000020c39500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007] >ffff000020c39580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]                                                        ^
[  +0.000007]  ffff000020c39600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000007]  ffff000020c39680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  +0.000006] ==================================================================

The reason this is happening is unloading meson-dw-hdmi will cause the
component API to take down the aggregate device, which in turn will cause
all devres-managed memory to be freed, including the struct dw_hdmi
allocated in dw_hdmi_probe. This struct embeds a struct drm_bridge that is
added at the end of the function, and which is later on picked up in
meson_encoder_hdmi_init.

However, when attaching the bridge to the encoder created in
meson_encoder_hdmi_init, it's linked to the encoder's bridge chain, from
where it never leaves, even after devres_release_group is called when the
driver's components are unbound and the embedding structure freed.

Then, when calling drm_dev_put in the aggregate driver's unbind function,
drm_bridge_detach is called for every single bridge linked to the encoder,
including the one whose memory had already been deallocated.

Fix by calling component_unbind_all after drm_dev_put.
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220919010940.419893-2-adrian.larumbe@collabora.com

Add comments on the lt8912_write_lvds_config() config to document the
current settings and to make it clear that this is a hardcoded
configuration not relevant for the HDMI output (could be removed without
affecting the HDMI port).

No changes on the actual register writes.
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-5-dev@pschenker.ch