I observed that the performance of the udl fb driver degrades over time.
On a freshly booted machine, it takes 6 seconds to do "ls -la /usr/bin";
after some time of use, the same operation takes 14 seconds.

The reason is that the value of "limit_sem" decays over time.

The udl driver uses a semaphore "limit_set" to specify how many free urbs
are there on dlfb->urbs.list. If the count is zero, the "down" operation
will sleep until some urbs are added to the freelist.

In order to avoid some hypothetical deadlock, the driver will not call
"up" immediately, but it will offload it to a workqueue. The problem is
that if we call "schedule_delayed_work" on the same work item multiple
times, the work item may only be executed once.

This is happening:
* some urb completes
* dlfb_urb_completion adds it to the free list
* dlfb_urb_completion calls schedule_delayed_work to schedule the function
  dlfb_release_urb_work to increase the semaphore count
* as the urb is on the free list, some other task grabs it and submits it
* the submitted urb completes, dlfb_urb_completion is called again
* dlfb_urb_completion calls schedule_delayed_work, but the work is already
  scheduled, so it does nothing
* finally, dlfb_release_urb_work is called, it increases the semaphore
  count by 1, although it should increase it by 2

So, the semaphore count is decreasing over time, and this causes gradual
performance degradation.

Note that in the current kernel, the "up" function may be called from
interrupt and it may race with the "down" function called by another
thread, so we don't have to offload the call of "up" to a workqueue at
all. This patch removes the workqueue code. The patch also changes
"down_interruptible" to "down" in dlfb_free_urb_list, so that we will
clean up the driver properly even if a signal arrives.

With this patch, the performance of udlfb no longer degrades.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
[b.zolnierkie: fix immediatelly -> immediately typo]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

I have a USB display adapter using the udlfb driver and I use it on an ARM
board that doesn't have any graphics card. When I plug the adapter in, the
console is properly displayed, however when I unplug and re-plug the
adapter, the console is not displayed and I can't access it until I reboot
the board.

The reason is this:
When the adapter is unplugged, dlfb_usb_disconnect calls
unlink_framebuffer, then it waits until the reference count drops to zero
and then it deallocates the framebuffer. However, the console that is
attached to the framebuffer device keeps the reference count non-zero, so
the framebuffer device is never destroyed. When the USB adapter is plugged
again, it creates a new device /dev/fb1 and the console is not attached to
it.

This patch fixes the bug by unbinding the console from unlink_framebuffer.
The code to unbind the console is moved from do_unregister_framebuffer to
a function unbind_console. When the console is unbound, the reference
count drops to zero and the udlfb driver frees the framebuffer. When the
adapter is plugged back, a new framebuffer is created and the console is
attached to it.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Ladislav Michl <ladis@linux-mips.org>
Cc: stable@vger.kernel.org
[b.zolnierkie: preserve old behavior for do_unregister_framebuffer()]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

On x86 some firmwares use a low non native resolution for the display when
they have shown some text messages. While keeping the bgrt filled with info
for the native resolution. If the bgrt image intended for the native
resolution still fits, it will be displayed very close to the right edge of
the display looking quite bad.

This commits adds a (heuristics based) checks for this and makes efifb
not show the boot graphics when this is the case.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Fix indentation warning (from gcc 8.1.0) in omap2/omapfb:

../drivers/video/fbdev/omap2/omapfb/dss/dispc.c: In function 'pixinc':
../drivers/video/fbdev/omap2/omapfb/dss/dispc.c:1859:2: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
  else
  ^~~~
../drivers/video/fbdev/omap2/omapfb/dss/dispc.c:1861:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'else'
   return 0;
   ^~~~~~
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Pointer 'in' is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'in' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

The value of tmp being used in the switch statement has the range of
just 0..3 hence the case 4 statement can never be reached and is
deadcode and can be removed.

Detected by CoverityScan, CID#744384 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

The omapfb_register_client[] array has OMAPFB_PLANE_NUM elements so the
> should be >= or we are one element beyond the end of the array.

Fixes: 8b08cf2b ("OMAP: add TI OMAP framebuffer driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Fix a build warning in viafbdev.c when CONFIG_PROC_FS is not enabled
by marking the unused function as __maybe_unused.

../drivers/video/fbdev/via/viafbdev.c:1471:12: warning: 'viafb_sup_odev_proc_show' defined but not used [-Wunused-function]
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

In a kernel configuration with both CONFIG_FB_OMAP=m and CONFIG_FB_OMAP2=m,
Kbuild fails to point out that we have two modules with the same name (omapfb.ko),
but instead fails with a cryptic error message like:

ERROR: "omapfb_register_panel" [drivers/video/fbdev/omap/lcd_osk.ko] undefined!

This can now happen when building a randconfig kernel with CONFIG_ARCH_OMAP1,
as the omap1 fbdev driver depends on that, whiel the omap2 fbdev driver can
now be built anywhere with CONFIG_COMPILE_TEST.

The solution is to rename one of the two modules, so for consistency with
the directory naming I decided to rename the omap2 version to omap2fb.ko.

Fixes: 7378f114 ("media: omap2: omapfb: allow building it with COMPILE_TEST")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

goldfish_fb_probe() allocates memory for fb, but goldfish_fb_remove() does
not have deallocation of fb, which leads to memory leak on probe/remove.

The patch adds deallocation into goldfish_fb_remove().

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Cc: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Fix up the indenting that confused sphinx. To make sure we
don't have to make the examples unreadable with escaping just
put them in as block quotes, that seems the simplest solution.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[b.zolnierkie: ported over fbdev changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

The "mem" buffer has "size" bytes.  The ">" should be ">=" to prevent
reading one character beyond the end of the array.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

It's been a pretty good while since kernel modesetting was introduced.
It has almost entirely replaced previous solutions which required
userspace modesetting, and I can't even recall any drivers off the top
of my head for modern day hardware that don't only support one or the
other. Even nvidia's ugly blob does not require the use of nomodeset,
and only requires that nouveau be blacklisted.

Effectively, the only thing nomodeset does in the year 2018 is disable
your graphics drivers. Since VESA is a thing, this will give many users
the false impression that they've actually fixed an issue they were
having with their machine simply because the laptop will boot up to a
degraded GUI. This of course, is never actually the case.

Things get even worse when you consider that there's still an enormous
amount of tutorials users find on the internet that still suggest adding
nomodeset, along with various users who have been around long enough to
still suggest it.

There really isn't any legitimate reason I can see for this to be an
option that's used by anyone else other then developers, or properly
informed users. So, let's end the confusion and start printing warnings
whenever it's enabled.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Jan H. Schönherr" <jschoenh@amazon.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Change beeng to being and occured to occurred.
Signed-off-by: Yisheng Xie <ysxie@foxmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Lechner <david@lechnology.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Following pattern is often used:

 for (i = 0; i < FB_MAX; i++) {
        if (registered_fb[i]) {
                ...
        }
 }

Therefore, as Andy's suggestion, for_each_registered_fb() helper can
be introduced to make the code easier to read and write by reducing
indentation level. It also saves few lines of code in each occurrence.

This patch convert all part here at the same time.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yisheng Xie <ysxie@foxmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Lechner <david@lechnology.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

In the quest to remove all stack VLA usage from the kernel[1], this moves
the buffer off the stack (since it could be as much as 1024 bytes), and
uses a new area in the cursor data structure. Additionally adds missed
documentation and removes redundant assignments.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.comSigned-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Timur Tabi <timur@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Optionally obtain a lcd-supply regulator during probe and use it in
__pxafb_lcd_power() to switch the power supply of LCD panels.

This helps boards booted from DT to control such voltages without
callbacks.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

pxafb_init_fbinfo() can not only report errors caused by failed
allocations but also when the clock can't be found.

To fix this, return an error pointer instead of NULL in case of errors,
and up-chain the result.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

This helps us clean up the probe() and remove() implementations.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

When parsing the video modes from DT properties, make sure to zero out
memory before using it. This is important because not all fields in the mode
struct are explicitly initialized, even though they are used later on.

Fixes: 420a4882 ("video: fbdev: pxafb: initial devicetree conversion")
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Add a device tree match table for this hardware graphics acceleration
driver so it can be used by pxa3xx boards booted with a devicetree.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

This patch adds the binding documentation for the pxa300 gcu.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

I discovered the problem when developing a frame buffer driver for the
PlayStation 2 (not yet merged), using the following video modes for the
PlayStation 3 in drivers/video/fbdev/ps3fb.c:

    }, {
        /* 1080if */
        "1080if", 50, 1920, 1080, 13468, 148, 484, 36, 4, 88, 5,
        FB_SYNC_BROADCAST, FB_VMODE_INTERLACED
    }, {
        /* 1080pf */
        "1080pf", 50, 1920, 1080, 6734, 148, 484, 36, 4, 88, 5,
        FB_SYNC_BROADCAST, FB_VMODE_NONINTERLACED
    },

In ps3fb_probe, the mode_option module parameter is used with fb_find_mode
but it can only select the interlaced variant of 1920x1080 since the loop
matching the modes does not take the difference between interlaced and
progressive modes into account.

In short, without the patch, progressive 1920x1080 cannot be chosen as a
mode_option parameter since fb_find_mode (falsely) thinks interlace is a
perfect match.
Signed-off-by: Fredrik Noring <noring@nocrew.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
[b.zolnierkie: updated patch description]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

On systems where fbcon is configured for deferred console takeover, the
intend is for the framebuffer to show the boot graphics (e.g a vendor
logo) until some message (e.g. an error) is printed or a graphical
session takes over.

Some firmware relies on the OS to show the boot graphics.

This patch adds support to efifb to show the boot graphics and
automatically enables this when fbcon is configured for deferred
console takeover.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

bgrt_image_size is necessary to (optionally) show the boot graphics from
the efifb code. The efifb driver is a platform driver, using a normal
driver probe() driver callback. So even though it is always builtin it
cannot reference __initdata.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Simplefb is not a clock provider, but it uses of_clk_get_parent_count(),
so it can just include <linux/of_clk.h> instead.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Return an error code on failure.

Problem found using Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

User space Android code identifies pixclock == 0 as a sign for emulation
and will set the frame rate to 60 fps when reading this value, which is
the desired outcome.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Add an ACPI id to make goldfish framebuffer to support ACPI enumeration.
Signed-off-by: Yu Ning <yu.ning@intel.com>
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Address issues pointed by checkpatch.pl
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Merge tag 'ib-fbdev-drm-v4.19-deferred-console-takeover-fixup' of https://github.com/bzolnier/linux into fbdev-for-next

Immutable branch between fbdev and drm for the v4.19 merge window
(contains build fixup for the deferred console takeover feature)

Export dummycon_[un]register_output_notifier, the fbcon code needs this
and may be build as a module.

Fixes: 83d83beb ("console/fbcon: Add support for deferred console takeover")
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Merge tag 'ib-fbdev-drm-v4.19-deferred-console-takeover' of https://github.com/bzolnier/linux into fbdev-for-next

Immutable branch between fbdev and drm for the v4.19 merge window
(contains the deferred console takeover feature)

Currently fbcon claims fbdevs as soon as they are registered and takes over
the console as soon as the first fbdev gets registered.

This behavior is undesirable in cases where a smooth graphical bootup is
desired, in such cases we typically want the contents of the framebuffer
(typically a vendor logo) to stay in place as is.

The current solution for this problem (on embedded systems) is to not
enable fbcon.

This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option,
which when enabled defers fbcon taking over the console from the dummy
console until the first text is displayed on the console. Together with the
"quiet" kernel commandline option, this allows fbcon to still be used
together with a smooth graphical bootup, having it take over the console as
soon as e.g. an error message is logged.

Note the choice to detect the first console output in the dummycon driver,
rather then handling this entirely inside the fbcon code, was made after
2 failed attempts to handle this entirely inside the fbcon code. The fbcon
code is woven quite tightly into the console code, making this to only
feasible option.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Replace comments about places where the console lock should be held with
calls to WARN_CONSOLE_UNLOCKED() to assert that it is actually held.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

This is a preparation patch for adding a number of WARN_CONSOLE_UNLOCKED()
calls to the fbcon code, which may be built as a module (event though
usually it is not).
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Merge tag 'v4.18-rc2' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 4.18-rc2