linux-stable.git/drivers/video/fbdev, branch v4.18.7 Linux kernel stable tree udlfb: set line_length in dlfb_ops_set_par 2018-09-09T08:32:41+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:56+00:00 fd13ae7e102a3e8dd4b45bd2dc12c61416331563 commit 0ac319b7af1bb24a33365d0ec82a2f56a59b2a78 upstream. Set the variable "line_length" in the function dlfb_ops_set_par. Without this, we get garbage if we select different videomode with fbset. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0ac319b7af1bb24a33365d0ec82a2f56a59b2a78 upstream.

Set the variable "line_length" in the function dlfb_ops_set_par. Without
this, we get garbage if we select different videomode with fbset.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: handle allocation failure 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:56+00:00 f551b193299b4212b66fbc44652a36f54b0fe0d7 commit 080fb5240bdcabed7387b814139c3ea172d59fc5 upstream. Allocations larger than PAGE_ALLOC_COSTLY_ORDER are unreliable and they may fail anytime. This patch fixes the udlfb driver so that when a large alloactions fails, it tries to do multiple smaller allocations. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 080fb5240bdcabed7387b814139c3ea172d59fc5 upstream.

Allocations larger than PAGE_ALLOC_COSTLY_ORDER are unreliable and they
may fail anytime. This patch fixes the udlfb driver so that when a large
alloactions fails, it tries to do multiple smaller allocations.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: make a local copy of fb_ops 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:55+00:00 0b5373ea72987884547c3a88c44cf93119c014e0 commit 2c29cfc3eaf11779176bf41475cfca49bccba11c upstream. The defio subsystem overwrites the method fb_osp->mmap. That method is stored in module's static data - and that means that if we have multiple diplaylink adapters, they will over write each other's method. In order to avoid interference between multiple adapters, we copy the fb_ops structure to a device-local memory. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2c29cfc3eaf11779176bf41475cfca49bccba11c upstream.

The defio subsystem overwrites the method fb_osp->mmap. That method is
stored in module's static data - and that means that if we have multiple
diplaylink adapters, they will over write each other's method.

In order to avoid interference between multiple adapters, we copy the
fb_ops structure to a device-local memory.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: don't switch if we are switching to the same videomode 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:55+00:00 76aab4b1d8044f3b1f1dc0e6f72760dc71b00f23 commit 564f1807379298dfdb12ed0d5b25fcb89c238527 upstream. The udlfb driver reprograms the hardware everytime the user switches the console, that makes quite unusable when working on the console. This patch makes the driver remember the videomode we are in and avoid reprogramming the hardware if we switch to the same videomode. We mask the "activate" field and the "FB_VMODE_SMOOTH_XPAN" flag when comparing the videomode, because they cause spurious switches when switching to and from the Xserver. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 564f1807379298dfdb12ed0d5b25fcb89c238527 upstream.

The udlfb driver reprograms the hardware everytime the user switches the
console, that makes quite unusable when working on the console.

This patch makes the driver remember the videomode we are in and avoid
reprogramming the hardware if we switch to the same videomode.

We mask the "activate" field and the "FB_VMODE_SMOOTH_XPAN" flag when
comparing the videomode, because they cause spurious switches when
switching to and from the Xserver.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: fix display corruption of the last line 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:54+00:00 1a5656245bd6d1f9b1bab1933a47a31f3d26b8b9 commit 4e705e17ce3409a1f492cfd5dadcf6a4f6075842 upstream. The displaylink hardware has such a peculiarity that it doesn't render a command until next command is received. This produces occasional corruption, such as when setting 22x11 font on the console, only the first line of the cursor will be blinking if the cursor is located at some specific columns. When we end up with a repeating pixel, the driver has a bug that it leaves one uninitialized byte after the command (and this byte is enough to flush the command and render it - thus it fixes the screen corruption), however whe we end up with a non-repeating pixel, there is no byte appended and this results in temporary screen corruption. This patch fixes the screen corruption by always appending a byte 0xAF at the end of URB. It also removes the uninitialized byte. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4e705e17ce3409a1f492cfd5dadcf6a4f6075842 upstream.

The displaylink hardware has such a peculiarity that it doesn't render a
command until next command is received. This produces occasional
corruption, such as when setting 22x11 font on the console, only the first
line of the cursor will be blinking if the cursor is located at some
specific columns.

When we end up with a repeating pixel, the driver has a bug that it leaves
one uninitialized byte after the command (and this byte is enough to flush
the command and render it - thus it fixes the screen corruption), however
whe we end up with a non-repeating pixel, there is no byte appended and
this results in temporary screen corruption.

This patch fixes the screen corruption by always appending a byte 0xAF at
the end of URB. It also removes the uninitialized byte.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: fix semaphore value leak 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:54+00:00 27f6b46dd248ce35f264e85ef97ea152eb6004d6 commit 9d0aa601e4cd9c0892f90d36e8488d79b72f4073 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9d0aa601e4cd9c0892f90d36e8488d79b72f4073 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fb: fix lost console when the user unplugs a USB adapter 2018-09-09T08:32:40+00:00 Mikulas Patocka mpatocka@redhat.com 2018-07-25T13:41:54+00:00 1a9ec6296e18426d2e4f177b66175f479f05a134 commit 8c5b044299951acd91e830a688dd920477ea1eda upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8c5b044299951acd91e830a688dd920477ea1eda upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental 2018-06-16T20:25:18+00:00 Linus Torvalds torvalds@linux-foundation.org 2018-06-16T20:25:18+00:00 5e7b9212a4a887f42221376445df52cd5991d100 Pull documentation fixes from Mauro Carvalho Chehab: "This solves a series of broken links for files under Documentation, and improves a script meant to detect such broken links (see scripts/documentation-file-ref-check). The changes on this series are: - can.rst: fix a footnote reference; - crypto_engine.rst: Fix two parsing warnings; - Fix a lot of broken references to Documentation/*; - improve the scripts/documentation-file-ref-check script, in order to help detecting/fixing broken references, preventing false-positives. After this patch series, only 33 broken references to doc files are detected by scripts/documentation-file-ref-check" * tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental: (26 commits) fix a series of Documentation/ broken file name references Documentation: rstFlatTable.py: fix a broken reference ABI: sysfs-devices-system-cpu: remove a broken reference devicetree: fix a series of wrong file references devicetree: fix name of pinctrl-bindings.txt devicetree: fix some bindings file names MAINTAINERS: fix location of DT npcm files MAINTAINERS: fix location of some display DT bindings kernel-parameters.txt: fix pointers to sound parameters bindings: nvmem/zii: Fix location of nvmem.txt docs: Fix more broken references scripts/documentation-file-ref-check: check tools/*/Documentation scripts/documentation-file-ref-check: get rid of false-positives scripts/documentation-file-ref-check: hint: dash or underline scripts/documentation-file-ref-check: add a fix logic for DT scripts/documentation-file-ref-check: accept more wildcards at filenames scripts/documentation-file-ref-check: fix help message media: max2175: fix location of driver's companion documentation media: v4l: fix broken video4linux docs locations media: dvb: point to the location of the old README.dvb-usb file ... 
Pull documentation fixes from Mauro Carvalho Chehab:
 "This solves a series of broken links for files under Documentation,
  and improves a script meant to detect such broken links (see
  scripts/documentation-file-ref-check).

  The changes on this series are:

   - can.rst: fix a footnote reference;

   - crypto_engine.rst: Fix two parsing warnings;

   - Fix a lot of broken references to Documentation/*;

   - improve the scripts/documentation-file-ref-check script, in order
     to help detecting/fixing broken references, preventing
     false-positives.

  After this patch series, only 33 broken references to doc files are
  detected by scripts/documentation-file-ref-check"

* tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental: (26 commits)
  fix a series of Documentation/ broken file name references
  Documentation: rstFlatTable.py: fix a broken reference
  ABI: sysfs-devices-system-cpu: remove a broken reference
  devicetree: fix a series of wrong file references
  devicetree: fix name of pinctrl-bindings.txt
  devicetree: fix some bindings file names
  MAINTAINERS: fix location of DT npcm files
  MAINTAINERS: fix location of some display DT bindings
  kernel-parameters.txt: fix pointers to sound parameters
  bindings: nvmem/zii: Fix location of nvmem.txt
  docs: Fix more broken references
  scripts/documentation-file-ref-check: check tools/*/Documentation
  scripts/documentation-file-ref-check: get rid of false-positives
  scripts/documentation-file-ref-check: hint: dash or underline
  scripts/documentation-file-ref-check: add a fix logic for DT
  scripts/documentation-file-ref-check: accept more wildcards at filenames
  scripts/documentation-file-ref-check: fix help message
  media: max2175: fix location of driver's companion documentation
  media: v4l: fix broken video4linux docs locations
  media: dvb: point to the location of the old README.dvb-usb file
  ...
Merge tag 'fbdev-v4.18' of git://github.com/bzolnier/linux 2018-06-16T20:00:24+00:00 Linus Torvalds torvalds@linux-foundation.org 2018-06-16T20:00:24+00:00 644f2639aef0c7a9a4f59b679375719d720d5461 Pull fbdev updates from Bartlomiej Zolnierkiewicz: "There is nothing really major here, few small fixes, some cleanups and dead drivers removal: - mark omapfb drivers as orphans in MAINTAINERS file (Tomi Valkeinen) - add missing module license tags to omap/omapfb driver (Arnd Bergmann) - add missing GPIOLIB dependendy to omap2/omapfb driver (Arnd Bergmann) - convert savagefb, aty128fb & radeonfb drivers to use msleep & co. (Jia-Ju Bai) - allow COMPILE_TEST build for viafb driver (media part was reviewed by media subsystem Maintainer) - remove unused MERAM support from sh_mobile_lcdcfb and shmob-drm drivers (drm parts were acked by shmob-drm driver Maintainer) - remove unused auo_k190xfb drivers - misc cleanups (Souptick Joarder, Wolfram Sang, Markus Elfring, Andy Shevchenko, Colin Ian King)" * tag 'fbdev-v4.18' of git://github.com/bzolnier/linux: (26 commits) fb_omap2: add gpiolib dependency video/omap: add module license tags MAINTAINERS: make omapfb orphan video: fbdev: pxafb: match_string() conversion fixup video: fbdev: nvidia: fix spelling mistake: "scaleing" -> "scaling" video: fbdev: fix spelling mistake: "frambuffer" -> "framebuffer" video: fbdev: pxafb: Convert to use match_string() helper video: fbdev: via: allow COMPILE_TEST build video: fbdev: remove unused sh_mobile_meram driver drm: shmobile: remove unused MERAM support video: fbdev: sh_mobile_lcdcfb: remove unused MERAM support video: fbdev: remove unused auo_k190xfb drivers video: omap: Improve a size determination in omapfb_do_probe() video: sm501fb: Improve a size determination in sm501fb_probe() video: fbdev-MMP: Improve a size determination in path_init() video: fbdev-MMP: Delete an error message for a failed memory allocation in two functions video: auo_k190x: Delete an error message for a failed memory allocation in auok190x_common_probe() video: sh_mobile_lcdcfb: Delete an error message for a failed memory allocation in two functions video: sh_mobile_meram: Delete an error message for a failed memory allocation in sh_mobile_meram_probe() video: fbdev: sh_mobile_meram: Drop SUPERH platform dependency ... 
Pull fbdev updates from Bartlomiej Zolnierkiewicz:
 "There is nothing really major here, few small fixes, some cleanups and
  dead drivers removal:

   - mark omapfb drivers as orphans in MAINTAINERS file (Tomi Valkeinen)

   - add missing module license tags to omap/omapfb driver (Arnd
     Bergmann)

   - add missing GPIOLIB dependendy to omap2/omapfb driver (Arnd
     Bergmann)

   - convert savagefb, aty128fb & radeonfb drivers to use msleep & co.
     (Jia-Ju Bai)

   - allow COMPILE_TEST build for viafb driver (media part was reviewed
     by media subsystem Maintainer)

   - remove unused MERAM support from sh_mobile_lcdcfb and shmob-drm
     drivers (drm parts were acked by shmob-drm driver Maintainer)

   - remove unused auo_k190xfb drivers

   - misc cleanups (Souptick Joarder, Wolfram Sang, Markus Elfring, Andy
     Shevchenko, Colin Ian King)"

* tag 'fbdev-v4.18' of git://github.com/bzolnier/linux: (26 commits)
  fb_omap2: add gpiolib dependency
  video/omap: add module license tags
  MAINTAINERS: make omapfb orphan
  video: fbdev: pxafb: match_string() conversion fixup
  video: fbdev: nvidia: fix spelling mistake: "scaleing" -> "scaling"
  video: fbdev: fix spelling mistake: "frambuffer" -> "framebuffer"
  video: fbdev: pxafb: Convert to use match_string() helper
  video: fbdev: via: allow COMPILE_TEST build
  video: fbdev: remove unused sh_mobile_meram driver
  drm: shmobile: remove unused MERAM support
  video: fbdev: sh_mobile_lcdcfb: remove unused MERAM support
  video: fbdev: remove unused auo_k190xfb drivers
  video: omap: Improve a size determination in omapfb_do_probe()
  video: sm501fb: Improve a size determination in sm501fb_probe()
  video: fbdev-MMP: Improve a size determination in path_init()
  video: fbdev-MMP: Delete an error message for a failed memory allocation in two functions
  video: auo_k190x: Delete an error message for a failed memory allocation in auok190x_common_probe()
  video: sh_mobile_lcdcfb: Delete an error message for a failed memory allocation in two functions
  video: sh_mobile_meram: Delete an error message for a failed memory allocation in sh_mobile_meram_probe()
  video: fbdev: sh_mobile_meram: Drop SUPERH platform dependency
  ...
docs: fix broken references with multiple hints 2018-06-15T21:10:01+00:00 Mauro Carvalho Chehab mchehab+samsung@kernel.org 2018-05-08T21:54:36+00:00 ec15872daa0ac3f5cbe7cb6f1734c493d74301ac The script: ./scripts/documentation-file-ref-check --fix Gives multiple hints for broken references on some files. Manually use the one that applies for some files. Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: James Morris <james.morris@microsoft.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Jonathan Corbet <corbet@lwn.net> 
The script:
	./scripts/documentation-file-ref-check --fix

Gives multiple hints for broken references on some files.
Manually use the one that applies for some files.

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>