Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by
selecting KMS FB helpers. A few provide a separate Kconfig option for the
user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top
level Kconfig option for fbdev emulation helps by providing a uniform way
to enable/disable fbdev emulation for any modesetting driver. It also lets
us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions
when not needed without breaking functionality. Having stub functions also
prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev
emulation by default and majority of distributions expect the fbdev
interface in the kernel.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

If CONFIG_MAGIC_SYSRQ is not set:

    drivers/gpu/drm/drm_fb_helper.c:390:13: warning: 'drm_fb_helper_force_kernel_mode' defined but not used [-Wunused-function]
     static bool drm_fb_helper_force_kernel_mode(void)
		 ^

Move drm_fb_helper_force_kernel_mode() inside the existing #ifdef to fix
this.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

As of commit 5ea1f752 ("drm: add
drm_fb_helper_restore_fbdev_mode_unlocked()"),
drm_fb_helper_restore_fbdev_mode() is no longer public, and drivers
should call drm_fb_helper_restore_fbdev_mode_unlocked() from their
->lastclose callbacks instead.

Update the documentation to reflect this, and absorb the one liner
drm_fb_helper_restore_fbdev_mode() into its single caller.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there
is no need to do that again from its callers. Drop it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- add missing header for virtgpu_fb.c

Cc: David Airlie <airlied@linux.ie>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- Fixed PTR_ERR issue mentioned by kbuild bot

Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- remove unused variable device in bochsfb_create

Cc: David Airlie <airlied@linux.ie>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- remove unused variable pdev in nouveau_fbcon_create

Cc: David Airlie <airlied@linux.ie>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- No changes

Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- Fix build break because of missing include of drm_fb_helper in
  radeon_drv.c

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- remove unused goto label 'out'

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v3:
- Update error handling for new drm_fb_helper funcs. Check using IS_ERR()
  instead of checking for NULL.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

v2:
- No changes

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly.

v3:
- Don't touch remove_conflicting_framebuffers

v2:
- Remove stray goto label out_iounmap

Cc: Thierry Reding <treding@nvidia.com>
Cc: Zach Reizner <zachr@google.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With

commit 7a3f3d66
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 9 23:44:28 2015 +0200

    drm: Check locking in drm_for_each_connector

we started checking the locking in drm_for_each_connector but somehow
I totally missed drm_mode_config_reset. There's no problem there since
this function should only be called in single-threaded contexts
(driver load or resume), so just wrap the loop with the right lock.

v2: Drink coffee and all that ...

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

The last user is gone, no need for trylocking any more in this legacy
helper.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Since the panic handling is gone this is only used for force-restoring
the fbdev/fbcon from sysrq, and that's done with a work item. No need
any more to do trylocks, we can just do normal locking.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Trying to do anything with kms drivers when oopsing has become a
failing proposition. But since we can end up in the fbdev code simply
due to the console unblanking that's done unconditionally just
removing our panic handler isn't enough. We need to block all fbdev
callbacks when oopsing.

There was already one in the blank handler, but it failed silently.
That makes it impossible for drivers (like i915) who subclass these
functions to figure this out.

Instead consistently return -EBUSY so that everyone knows that we
really don't want to be bothered right now. This also allows us to
remove a pile of FIXMEs from the i915 fbdev code (since due to the
failure code they now won't attempt to grab dangerous locks any more).

Cc: Dave Airlie <airlied@gmail.com>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v2:
- remove unused variable device in udlfb_create

Cc: David Airlie <airlied@linux.ie>
Cc: Haixia Shi <hshi@chromium.org>
Cc: "Stéphane Marchesin" <marcheu@chromium.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

Cc: David Airlie <airlied@linux.ie>
Cc: Frediano Ziglio <fziglio@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v2:
- removed unused variable 'device' in psbfb_create

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v2:
- Remove unnecessary dealloc cmap in error handling path

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Stephane Viau <sviau@codeaurora.org>
Cc: Hai Li <hali@codeaurora.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

v2:
- Fix up error handling path in tegra_fbdev_probe

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: "Terje Bergström" <tbergstrom@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

Cleaned up the error handling in astfb_create a bit.

v2:
- removed unused variable 'device' in astfb_create

Cc: David Airlie <airlied@linux.ie>
Cc: "Y.C. Chen" <yc_chen@aspeedtech.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Use the newly created wrapper drm_fb_helper functions instead of calling
core fbdev functions directly. They also simplify the fb_info creation.

This is an effort to create a top level drm fbdev emulation option.

Cc: Mark Yao <mark.yao@rock-chips.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Some drm drivers call fb_set_suspend. Create a drm_fb_helper function
that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fixed kerneldoc errors

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation
- Follow the drm way of aligning of arguments in func definitions
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drm drivers that emulate fbdev populate their fb_fillrect, fb_copyarea
and fb_imageblit fb_ops with the help of cfb_* or sys_* fbdev core
helper functions.

Create drm_fb_helper functions that wrap around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fixed kerneldoc errors

v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
- Remove unnecessary checks for non NULL fb_info
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Some drm drivers populate their fb_ops with fb_sys_read/write fb sysfs
ops.

Create a drm_fb_helper function that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fix kerneldoc errors

v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
- Remove unnecessary checks for non NULL fb_info
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Some drm drivers call unlink_framebuffer. Create a drm_fb_helper function
that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Every drm driver calls framebuffer_alloc, fb_alloc_cmap,
unregister_framebuffer, fb_dealloc_cmap and framebuffer_release in
order to emulate fbdev support.

Create drm_fb_helper functions that perform the above operations.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly. It also removes repetitive code from drivers.

There are some drivers that call alloc_apertures after framebuffer_alloc
and some that don't. Make the helper always call alloc_apertures. This
would make certain drivers allocate memory for apertures but not use
them. Since it's a small amount of memory, it shouldn't be an issue.

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Maarten didn't fully test his patches on all drm drivers and
apparently missed a few places when grepping.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

This is required for DPMS to work correctly, during a modeset
the DPMS property should be turned off, unless the state is
crtc is made active in which case it should be set to DPMS on.

Changes since v1:
- Set DPMS to off when a connector is removed from a crtc too.
- Update the legacy dpms property too.
- Add an exception for the legacy dpms paths, it updates its own state.
Changes since v2:
- Do not preserve dpms property.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This is required to properly handle failing dpms calls.
When making a wait in i915 interruptible, I've noticed
that the dpms sequence could fail with -ERESTARTSYS because
it was waiting interruptibly for flips. So from now on
allow drivers to fail in their connector dpms callback.

Encoder and crtc dpms callbacks are unaffected.

Changes since v1:
- Update kerneldoc for the drm helper functions.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Resolve conflicts due to different merge order.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

In intel it's useful to keep track of some state changes with old
crtc state vs new state, for example to disable initial planes or
when a modeset's prevented during fastboot.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
[danvet: squash in fixup for exynos provided by Maarten.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This can be a separate case from mode_changed, when connectors stay the
same but only the mode is different. Drivers may choose to implement specific
optimizations to prevent a full modeset for this case.

Changes since v1:
- Update kerneldocs slightly.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

By Vesa's DP 1.2 Spec this counter has 4 bits [3:0].

This mask is wrong since when the counter was introduced by myself
on commit ad9dc91b
Author: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Date:   Tue Sep 16 19:18:12 2014 -0400

    drm/i915: Fix Sink CRC
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Merge tag 'topic/connector-locking-2015-07-23' of git://anongit.freedesktop.org/drm-intel into drm-next

connector hotplug locking cleanup and fixes to make it save against
atomic. Note that because of depencies this is based on top of the
drm-intel-next pull, so that one needs to go in before this one.

I've also thrown in the mode_group removal on top since it's defunct,
never worked really, no one seems to care and the code can be resurrected
easily.

* tag 'topic/connector-locking-2015-07-23' of git://anongit.freedesktop.org/drm-intel:
  drm: gc now dead mode_group code
  drm: Stop filtering according to mode_group in getresources
  drm: Roll out drm_for_each_{plane,crtc,encoder}
  drm/cma-helper: Fix locking in drm_fb_cma_debugfs_show
  drm: Roll out drm_for_each_connector more
  drm: Amend connector list locking rules
  drm/radeon: Take all modeset locks for DP MST hotplug
  drm/i915: Take all modeset locks for DP MST hotplug
  drm: Check locking in drm_for_each_fb
  drm/i915: Use drm_for_each_fb in i915_debugfs.c
  drm: Check locking in drm_for_each_connector
  drm/fbdev-helper: Grab mode_config.mutex in drm_fb_helper_single_add_all_connectors
  drm/probe-helper: Grab mode_config.mutex in poll_init/enable
  drm: Add modeset object iterators
  drm: Simplify drm_for_each_legacy_plane arguments

crystalcove pmic support from Shobhit. Patch series has all acks/r-bs from
other mainainers so ok to pull into drm-next. But I'm cc'ing all other
maintainers as fyi and in case they want to pull it into their trees too
to avoid conflicts.

* tag 'topic/crc-pmic-2015-07-23' of git://anongit.freedesktop.org/drm-intel:
  mfd: Add GPIOLIB dependency if INTEL_SOC_PMIC is to be enabled
  drm/i915: Backlight control using CRC PMIC based PWM driver
  drm/i915: Use the CRC gpio for panel enable/disable
  pwm: crc: Add Crystalcove (CRC) PWM driver
  mfd: intel_soc_pmic_core: ADD PWM lookup table for CRC PMIC based PWM
  mfd: intel_soc_pmic_crc: Add PWM cell device for Crystalcove PMIC
  mfd: intel_soc_pmic_core: Add lookup table for Panel Control as GPIO signal
  gpiolib: Add support for removing registered consumer lookup table