<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/drivers/video/fbdev/udlfb.c, branch v6.1.168</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.1.168</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.1.168'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2023-05-30T13:03:20+00:00</updated>
<entry>
<title>fbdev: udlfb: Fix endpoint check</title>
<updated>2023-05-30T13:03:20+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2023-05-19T19:32:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c8fdf7feca77cd99e25ef0a1e9e72dfc83add8ef'/>
<id>urn:sha1:c8fdf7feca77cd99e25ef0a1e9e72dfc83add8ef</id>
<content type='text'>
commit ed9de4ed39875706607fb08118a58344ae6c5f42 upstream.

The syzbot fuzzer detected a problem in the udlfb driver, caused by an
endpoint not having the expected type:

usb 1-1: Read EDID byte 0 failed: -71
usb 1-1: Unable to get valid EDID from device/display
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880
drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted
6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
04/28/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
 &lt;TASK&gt;
 dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980
 dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315
 dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111
 dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743

The current approach for this issue failed to catch the problem
because it only checks for the existence of a bulk-OUT endpoint; it
doesn't check whether this endpoint is the one that the driver will
actually use.

We can fix the problem by instead checking that the endpoint used by
the driver does exist and is bulk-OUT.

Reported-and-tested-by: syzbot+0e22d63dcebb802b9bc8@syzkaller.appspotmail.com
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Pavel Skripkin &lt;paskripkin@gmail.com&gt;
Fixes: aaf7dbe07385 ("video: fbdev: udlfb: properly check endpoint type")
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>fbdev: udlfb: Remove redundant initialization to variable identical</title>
<updated>2022-10-08T13:20:08+00:00</updated>
<author>
<name>Colin Ian King</name>
<email>colin.i.king@gmail.com</email>
</author>
<published>2022-09-07T13:50:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=59945216889518982d262d4cab099c6554f58867'/>
<id>urn:sha1:59945216889518982d262d4cab099c6554f58867</id>
<content type='text'>
The variable identical is being initialized with a value that is never
read. The variable is being re-assigned later on. The initialization is
redundant and can be removed.

Cleans up clang scan-build warning:
drivers/video/fbdev/udlfb.c:373:6: warning: Value stored to 'identical'
during its initialization is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King &lt;colin.i.king@gmail.com&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
</content>
</entry>
<entry>
<title>fbdev: Use pageref offset for deferred-I/O writeback</title>
<updated>2022-05-03T14:04:22+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-04-29T10:08:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e2d8b4289c937447ab710052f15a18f686db73dc'/>
<id>urn:sha1:e2d8b4289c937447ab710052f15a18f686db73dc</id>
<content type='text'>
Use pageref-&gt;offset instead of page-&gt;index for deferred-I/O writeback
where appropriate. Distinguishes between file-mapping offset and video-
memory offset. While at it, also remove unnecessary references to
struct page.

Fbdev's deferred-I/O code uses the two related page-&gt;index and
pageref-&gt;offset. The former is the page offset in the mapped file,
the latter is the byte offset in the video memory (or fbdev screen
buffer). It's the same value for fbdev drivers, but for DRM the values
can be different. Because GEM buffer objects are mapped at an offset
in the DRM device file, page-&gt;index has this offset added to it as well.
We currently don't hit this case in DRM, because all affected mappings
of GEM memory are performed with an internal, intermediate shadow buffer.

The value of page-&gt;index is required by page_mkclean(), which we
call to reset the mappings during the writeback phase of the deferred
I/O. The value of pageref-&gt;offset is for conveniently getting an offset
into video memory in fb helpers.

v4:
	* fix commit message (Javier)

Suggested-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-6-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>fbdev: Rename pagelist to pagereflist for deferred I/O</title>
<updated>2022-05-03T14:04:22+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-04-29T10:08:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e80eec1b871a2acb8f5c92db4c237e9ae6dd322b'/>
<id>urn:sha1:e80eec1b871a2acb8f5c92db4c237e9ae6dd322b</id>
<content type='text'>
Rename various instances of pagelist to pagereflist. The list now
stores pageref structures, so the new name is more appropriate.

In their write-back helpers, several fbdev drivers refer to the
pageref list in struct fb_deferred_io instead of using the one
supplied as argument to the function. Convert them over to the
supplied one. It's the same instance, so no change of behavior
occurs.

v4:
	* fix commit message (Javier)

Suggested-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-5-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>fbdev: Track deferred-I/O pages in pageref struct</title>
<updated>2022-05-03T14:04:22+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-04-29T10:08:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=56c134f7f1b58be08bdb0ca8372474a4a5165f31'/>
<id>urn:sha1:56c134f7f1b58be08bdb0ca8372474a4a5165f31</id>
<content type='text'>
Store the per-page state for fbdev's deferred I/O in struct
fb_deferred_io_pageref. Maintain a list of pagerefs for the pages
that have to be written back to video memory. Update all affected
drivers.

As with pages before, fbdev acquires a pageref when an mmaped page
of the framebuffer is being written to. It holds the pageref in a
list of all currently written pagerefs until it flushes the written
pages to video memory. Writeback occurs periodically. After writeback
fbdev releases all pagerefs and builds up a new dirty list until the
next writeback occurs.

Using pagerefs has a number of benefits.

For pages of the framebuffer, the deferred I/O code used struct
page.lru as an entry into the list of dirty pages. The lru field is
owned by the page cache, which makes deferred I/O incompatible with
some memory pages (e.g., most notably DRM's GEM SHMEM allocator).
struct fb_deferred_io_pageref now provides an entry into a list of
dirty framebuffer pages, freeing lru for use with the page cache.

Drivers also assumed that struct page.index is the page offset into
the framebuffer. This is not true for DRM buffers, which are located
at various offset within a mapped area. struct fb_deferred_io_pageref
explicitly stores an offset into the framebuffer. struct page.index
is now only the page offset into the mapped area.

These changes will allow DRM to use fbdev deferred I/O without an
intermediate shadow buffer.

v3:
	* use pageref-&gt;offset for sorting
	* fix grammar in comment
v2:
	* minor fixes in commit message

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-3-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>fbdev: Put mmap for deferred I/O into drivers</title>
<updated>2022-05-03T14:04:21+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-04-29T10:08:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5905585103276b7c14bb9a7de4b575216cb6dac4'/>
<id>urn:sha1:5905585103276b7c14bb9a7de4b575216cb6dac4</id>
<content type='text'>
The fbdev mmap function fb_mmap() unconditionally overrides the
driver's implementation if deferred I/O has been activated. This
makes it hard to implement mmap with anything but a vmalloc()'ed
software buffer. That is specifically a problem for DRM, where
video memory is maintained by a memory manager.

Leave the mmap handling to drivers and expect them to call the
helper for deferred I/O by thmeselves.

v4:
	* unlock mm_lock in fb_mmap() error path (Dan)
v3:
	* fix warning if fb_mmap is missing (kernel test robot)
v2:
	* print a helpful error message if the defio setup is
	  incorrect (Javier)

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-2-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>video: fbdev: udlfb: properly check endpoint type</title>
<updated>2022-04-04T06:55:23+00:00</updated>
<author>
<name>Pavel Skripkin</name>
<email>paskripkin@gmail.com</email>
</author>
<published>2022-03-22T20:04:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=aaf7dbe07385e0b8deb7237eca2a79926bbc7091'/>
<id>urn:sha1:aaf7dbe07385e0b8deb7237eca2a79926bbc7091</id>
<content type='text'>
syzbot reported warning in usb_submit_urb, which is caused by wrong
endpoint type.

This driver uses out bulk endpoint for communication, so
let's check if this endpoint is present and bail out early if not.

Fail log:

usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 4822 at drivers/usb/core/urb.c:493 usb_submit_urb+0xd27/0x1540 drivers/usb/core/urb.c:493
Modules linked in:
CPU: 0 PID: 4822 Comm: kworker/0:3 Tainted: G        W         5.13.0-syzkaller #0
...
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xd27/0x1540 drivers/usb/core/urb.c:493
...
Call Trace:
 dlfb_submit_urb+0x89/0x160 drivers/video/fbdev/udlfb.c:1969
 dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315
 dlfb_ops_set_par+0x2a3/0x840 drivers/video/fbdev/udlfb.c:1110
 dlfb_usb_probe.cold+0x113e/0x1f4a drivers/video/fbdev/udlfb.c:1732
 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396

Fixes: 88e58b1a42f8 ("Staging: add udlfb driver")
Reported-and-tested-by: syzbot+53ce4a4246d0fe0fee34@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin &lt;paskripkin@gmail.com&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
</content>
</entry>
<entry>
<title>Merge tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm</title>
<updated>2022-03-24T23:19:43+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-03-24T23:19:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b14ffae378aa1db993e62b01392e70d1e585fb23'/>
<id>urn:sha1:b14ffae378aa1db993e62b01392e70d1e585fb23</id>
<content type='text'>
Pull drm updates from Dave Airlie:
 "Lots of work all over, Intel improving DG2 support, amdkfd CRIU
  support, msm new hw support, and faster fbdev support.

  dma-buf:
   - rename dma-buf-map to iosys-map

  core:
   - move buddy allocator to core
   - add pci/platform init macros
   - improve EDID parser deep color handling
   - EDID timing type 7 support
   - add GPD Win Max quirk
   - add yes/no helpers to string_helpers
   - flatten syncobj chains
   - add nomodeset support to lots of drivers
   - improve fb-helper clipping support
   - add default property value interface

  fbdev:
   - improve fbdev ops speed

  ttm:
   - add a backpointer from ttm bo-&gt;ttm resource

  dp:
   - move displayport headers
   - add a dp helper module

  bridge:
   - anx7625 atomic support, HDCP support

  panel:
   - split out panel-lvds and lvds bindings
   - find panels in OF subnodes

  privacy:
   - add chromeos privacy screen support

  fb:
   - hot unplug fw fb on forced removal

  simpledrm:
   - request region instead of marking ioresource busy
   - add panel oreintation property

  udmabuf:
   - fix oops with 0 pages

  amdgpu:
   - power management code cleanup
   - Enable freesync video mode by default
   - RAS code cleanup
   - Improve VRAM access for debug using SDMA
   - SR-IOV rework special register access and fixes
   - profiling power state request ioctl
   - expose IP discovery via sysfs
   - Cyan skillfish updates
   - GC 10.3.7, SDMA 5.2.7, DCN 3.1.6 updates
   - expose benchmark tests via debugfs
   - add module param to disable XGMI for testing
   - GPU reset debugfs register dumping support

  amdkfd:
   - CRIU support
   - SDMA queue fixes

  radeon:
   - UVD suspend fix
   - iMac backlight fix

  i915:
   - minimal parallel submission for execlists
   - DG2-G12 subplatform added
   - DG2 programming workarounds
   - DG2 accelerated migration support
   - flat CCS and CCS engine support for XeHP
   - initial small BAR support
   - drop fake LMEM support
   - ADL-N PCH support
   - bigjoiner updates
   - introduce VMA resources and async unbinding
   - register definitions cleanups
   - multi-FBC refactoring
   - DG1 OPROM over SPI support
   - ADL-N platform enabling
   - opregion mailbox #5 support
   - DP MST ESI improvements
   - drm device based logging
   - async flip optimisation for DG2
   - CPU arch abstraction fixes
   - improve GuC ADS init to work on aarch64
   - tweak TTM LRU priority hint
   - GuC 69.0.3 support
   - remove short term execbuf pins

  nouveau:
   - higher DP/eDP bitrates
   - backlight fixes

  msm:
   - dpu + dp support for sc8180x
   - dp support for sm8350
   - dpu + dsi support for qcm2290
   - 10nm dsi phy tuning support
   - bridge support for dp encoder
   - gpu support for additional 7c3 SKUs

  ingenic:
   - HDMI support for JZ4780
   - aux channel EDID support

  ast:
   - AST2600 support
   - add wide screen support
   - create DP/DVI connectors

  omapdrm:
   - fix implicit dma_buf fencing

  vc4:
   - add CSC + full range support
   - better display firmware handoff

  panfrost:
   - add initial dual-core GPU support

  stm:
   - new revision support
   - fb handover support

  mediatek:
   - transfer display binding document to yaml format.
   - add mt8195 display device binding.
   - allow commands to be sent during video mode.
   - add wait_for_event for crtc disable by cmdq.

  tegra:
   - YUV format support

  rcar-du:
   - LVDS support for M3-W+ (R8A77961)

  exynos:
   - BGR pixel format for FIMD device"

* tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm: (1529 commits)
  drm/i915/display: Do not re-enable PSR after it was marked as not reliable
  drm/i915/display: Fix HPD short pulse handling for eDP
  drm/amdgpu: Use drm_mode_copy()
  drm/radeon: Use drm_mode_copy()
  drm/amdgpu: Use ternary operator in `vcn_v1_0_start()`
  drm/amdgpu: Remove pointless on stack mode copies
  drm/amd/pm: fix indenting in __smu_cmn_reg_print_error()
  drm/amdgpu/dc: fix typos in comments
  drm/amdgpu: fix typos in comments
  drm/amd/pm: fix typos in comments
  drm/amdgpu: Add stolen reserved memory for MI25 SRIOV.
  drm/amdgpu: Merge get_reserved_allocation to get_vbios_allocations.
  drm/amdkfd: evict svm bo worker handle error
  drm/amdgpu/vcn: fix vcn ring test failure in igt reload test
  drm/amdgpu: only allow secure submission on rings which support that
  drm/amdgpu: fixed the warnings reported by kernel test robot
  drm/amd/display: 3.2.177
  drm/amd/display: [FW Promotion] Release 0.0.108.0
  drm/amd/display: Add save/restore PANEL_PWRSEQ_REF_DIV2
  drm/amd/display: Wait for hubp read line for Pollock
  ...
</content>
</entry>
<entry>
<title>fbdev: Don't sort deferred-I/O pages by default</title>
<updated>2022-02-16T15:41:45+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-02-11T09:46:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8c30e2d81bfddc5ab9f6b04db1c0f7d6ca7bdf46'/>
<id>urn:sha1:8c30e2d81bfddc5ab9f6b04db1c0f7d6ca7bdf46</id>
<content type='text'>
Fbdev's deferred I/O sorts all dirty pages by default, which incurs a
significant overhead. Make the sorting step optional and update the few
drivers that require it. Use a FIFO list by default.

Most fbdev drivers with deferred I/O build a bounding rectangle around
the dirty pages or simply flush the whole screen. The only two affected
DRM drivers, generic fbdev and vmwgfx, both use a bounding rectangle.
In those cases, the exact order of the pages doesn't matter. The other
drivers look at the page index or handle pages one-by-one. The patch
sets the sort_pagelist flag for those, even though some of them would
probably work correctly without sorting. Driver maintainers should update
their driver accordingly.

Sorting pages by memory offset for deferred I/O performs an implicit
bubble-sort step on the list of dirty pages. The algorithm goes through
the list of dirty pages and inserts each new page according to its
index field. Even worse, list traversal always starts at the first
entry. As video memory is most likely updated scanline by scanline, the
algorithm traverses through the complete list for each updated page.

For example, with 1024x768x32bpp each page covers exactly one scanline.
Writing a single screen update from top to bottom requires updating
768 pages. With an average list length of 384 entries, a screen update
creates (768 * 384 =) 294912 compare operation.

Fix this by making the sorting step opt-in and update the few drivers
that require it. All other drivers work with unsorted page lists. Pages
are appended to the list. Therefore, in the common case of writing the
framebuffer top to bottom, pages are still sorted by offset, which may
have a positive effect on performance.

Playing a video [1] in mplayer's benchmark mode shows the difference
(i7-4790, FullHD, simpledrm, kernel with debugging).

  mplayer -benchmark -nosound -vo fbdev ./big_buck_bunny_720p_stereo.ogg

With sorted page lists:

  BENCHMARKs: VC:  32.960s VO:  73.068s A:   0.000s Sys:   2.413s =  108.441s
  BENCHMARK%: VC: 30.3947% VO: 67.3802% A:  0.0000% Sys:  2.2251% = 100.0000%

With unsorted page lists:

  BENCHMARKs: VC:  31.005s VO:  42.889s A:   0.000s Sys:   2.256s =   76.150s
  BENCHMARK%: VC: 40.7156% VO: 56.3219% A:  0.0000% Sys:  2.9625% = 100.0000%

VC shows the overhead of video decoding, VO shows the overhead of the
video output. Using unsorted page lists reduces the benchmark's run time
by ~32s/~25%.

v2:
	* Make sorted pagelists the special case (Sam)
	* Comment on drivers' use of pagelist (Sam)
	* Warn about the overhead in comment

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Acked-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Acked-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://download.blender.org/peach/bigbuckbunny_movies/big_buck_bunny_720p_stereo.ogg # [1]
Link: https://patchwork.freedesktop.org/patch/msgid/20220211094640.21632-3-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>video: fbdev: udlfb: replace snprintf in show functions with sysfs_emit</title>
<updated>2022-02-11T10:28:33+00:00</updated>
<author>
<name>Jing Yao</name>
<email>yao.jing2@zte.com.cn</email>
</author>
<published>2021-11-04T11:52:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=81a998288956d09d7a7a2303d47e4d60ad55c401'/>
<id>urn:sha1:81a998288956d09d7a7a2303d47e4d60ad55c401</id>
<content type='text'>
Use sysfs_emit instead of scnprintf, snprintf or sprintf.

Reported-by: Zeal Robot &lt;zealci@zte.com.cn&gt;
Signed-off-by: Jing Yao &lt;yao.jing2@zte.com.cn&gt;
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
</content>
</entry>
</feed>
