<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/Documentation/gpu/todo.rst, branch v5.19</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.19</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.19'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2022-05-05T08:09:06+00:00</updated>
<entry>
<title>drm/todo: Add entry for using kunit in the subsystem</title>
<updated>2022-05-05T08:09:06+00:00</updated>
<author>
<name>Javier Martinez Canillas</name>
<email>javierm@redhat.com</email>
</author>
<published>2022-05-04T08:02:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=596c35b1440e7e8a954c87ae73b3f7c4e877b055'/>
<id>urn:sha1:596c35b1440e7e8a954c87ae73b3f7c4e877b055</id>
<content type='text'>
The Kernel Unit Testing (KUnit) framework provides a common framework for
unit tests within the Linux kernel. Having a test suite would allow to
identify regressions earlier.

Signed-off-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Acked-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Acked-by: Maxime Ripard &lt;maxime@cerno.tech&gt;
Acked-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220504080212.713275-1-javierm@redhat.com
</content>
</entry>
<entry>
<title>Merge tag 'drm-misc-next-2022-03-03' of git://anongit.freedesktop.org/drm/drm-misc into drm-next</title>
<updated>2022-03-04T03:41:57+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2022-03-04T03:41:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c9e9ce0b6f85ac330adee912745048a0af5f315d'/>
<id>urn:sha1:c9e9ce0b6f85ac330adee912745048a0af5f315d</id>
<content type='text'>
drm-misc-next for v5.18:

UAPI Changes:

Cross-subsystem Changes:
- Improve performance of some fbdev ops, in some cases up to 6x faster.

Core Changes:
- Some small DP fixes.
- Find panels in subnodes of OF devices, and add of_get_drm_panel_display_mode
  to retrieve mode.
- Add drm_object_property_get_default_value and use it for resetting
  zpos in plane state reset, removing the need for individual drivers
  to do it.
- Same for color encoding and color range props.
- Update panic handling todo doc.
- Add todo that format conversion helpers should be sped up similarly to fbdev ops.

Driver Changes:
- Add panel orientation property to simpledrm for quirked panels.
- Assorted small fixes to tiny/repaper, nouveau, stm, omap, ssd130x.
- Add crc support to stm/ltdc.
- Add MIPI DBI compatible SPI driver
- Assorted small fixes to tiny panels and bridge drivers.
- Add AST2600 support to aspeed.

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;

From: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/48fabd78-ade9-f80b-c724-13726c7be69e@linux.intel.com
</content>
</entry>
<entry>
<title>drm: Add TODO item for optimizing format helpers</title>
<updated>2022-03-02T19:26:02+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-02-23T19:38:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9ae2ac4d31a85ce59cc560d514a31b95f4ace154'/>
<id>urn:sha1:9ae2ac4d31a85ce59cc560d514a31b95f4ace154</id>
<content type='text'>
Add a TODO item for optimizing blitting and format-conversion helpers
in DRM and fbdev. There's always demand for faster graphics output.

v4:
	* fix typos (Sam)

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Acked-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220223193804.18636-6-tzimmermann@suse.de
</content>
</entry>
<entry>
<title>drm/todo: Update panic handling todo</title>
<updated>2022-02-28T08:58:42+00:00</updated>
<author>
<name>Daniel Vetter</name>
<email>daniel.vetter@ffwll.ch</email>
</author>
<published>2022-02-24T13:24:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4db3189ce0621be901f249f8cd8226c977dd601d'/>
<id>urn:sha1:4db3189ce0621be901f249f8cd8226c977dd601d</id>
<content type='text'>
Some things changed, and add two useful links.

v2: Also include a link to the QR encoding work. Plus review from
Javier.

v3: Fix typo Guilherme spotted.

Reviewed-by: Guilherme G. Piccoli &lt;gpiccoli@igalia.com&gt;
Acked-by: Pekka Paalanen &lt;pekka.paalanen@collabora.com&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Cc: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Cc: Pekka Paalanen &lt;ppaalanen@gmail.com&gt;
Cc: gpiccoli@igalia.com
Signed-off-by: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220224132425.3463791-1-daniel.vetter@ffwll.ch
</content>
</entry>
<entry>
<title>Backmerge tag 'v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into drm-next</title>
<updated>2022-02-14T00:52:27+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2022-02-14T00:52:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b9c7babe2c2e37a50aa42401b38d597ea78f506e'/>
<id>urn:sha1:b9c7babe2c2e37a50aa42401b38d597ea78f506e</id>
<content type='text'>
Daniel asked for this for some intel deps, so let's do it now.

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'drm-intel-next-2022-02-08' of git://anongit.freedesktop.org/drm/drm-intel into drm-next</title>
<updated>2022-02-11T04:14:07+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2022-02-11T04:13:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e7a09cea6483b44ea0c82f07145fcbd8a918bf96'/>
<id>urn:sha1:e7a09cea6483b44ea0c82f07145fcbd8a918bf96</id>
<content type='text'>
Cross-subsystem Changes:
------------------------

dma-buf:
- dma-buf-map: Rename to iosys-map (Lucas)

Core Changes:
-------------

drm:
- Always include the debugfs_entry in drm_crtc (Ville)
- Add orientation quirk for GPD Win Max (Anisse)

Driver Changes:
---------------

gvt:
- Constify some pointers. (Rikard Falkeborn)
- Use list_entry to access list members. (Guenter Roeck)
- Fix cmd parser error for Passmark9. (Zhenyu Wang)

i915:
- Various clean-ups including headers and removing unused and unnecessary stuff\
 (Jani, Hans, Andy, Ville)
- Cleaning up on our registers definitions i915_reg.h (Matt)
- More multi-FBC refactoring (Ville)
- Baytrail backlight fix (Hans)
- DG1 OPROM read through SPI controller (Clint)
- ADL-N platform enabling (Tejas)
- Fix slab-out-of-bounds access (Jani)
- Add opregion mailbox #5 support for possible EDID override (Anisse)
- Fix possible NULL dereferences (Harish)
- Updates and fixes around display voltage swing values (Clint, Jose)
- Fix RPM wekeref on PXP code (Juston)
- Many register definitions clean-up, including planes registers (Ville)
- More conversion towards display version over the old gen (Madhumitha, Ville)
- DP MST ESI handling improvements (Jani)
- drm device based logging conversions (Jani)
- Prevent divide by zero (Dan)
- Introduce ilk_pch_pre_enable for complete modeset abstraction (Ville)
- Async flip optimization for DG2 (Stanislav)
- Multiple DSC and bigjoiner fixes and improvements (Ville)
- Fix ADL-P TypeC Phy ready status readout (Imre)
- Fix up DP DFP 4:2:0 handling more display related fixes (Ville)
- Display M/N cleanup (Ville)
- Switch to use VGA definitions from video/vga.h (Jani)
- Fixes and improvements to abstract CPU architecture (Lucas)
- Disable unsused power wells left enabled by BIOS (Imre)
- Allow !join_mbus cases for adlp+ dbuf configuration (Ville)
- Populate pipe dbuf slices more accurately during readout (Ville)
- Workaround broken BIOS DBUF configuration on TGL/RKL (Ville)
- Fix trailing semicolon (Lucas)

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;

From: Rodrigo Vivi &lt;rodrigo.vivi@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/YgKFLmCgpv4vQEa1@intel.com
</content>
</entry>
<entry>
<title>dma-buf-map: Rename to iosys-map</title>
<updated>2022-02-08T00:35:35+00:00</updated>
<author>
<name>Lucas De Marchi</name>
<email>lucas.demarchi@intel.com</email>
</author>
<published>2022-02-04T17:05:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=7938f4218168ae9fc4bdddb15976f9ebbae41999'/>
<id>urn:sha1:7938f4218168ae9fc4bdddb15976f9ebbae41999</id>
<content type='text'>
Rename struct dma_buf_map to struct iosys_map and corresponding APIs.
Over time dma-buf-map grew up to more functionality than the one used by
dma-buf: in fact it's just a shim layer to abstract system memory, that
can be accessed via regular load and store, from IO memory that needs to
be acessed via arch helpers.

The idea is to extend this API so it can fulfill other needs, internal
to a single driver. Example: in the i915 driver it's desired to share
the implementation for integrated graphics, which uses mostly system
memory, with discrete graphics, which may need to access IO memory.

The conversion was mostly done with the following semantic patch:

	@r1@
	@@
	- struct dma_buf_map
	+ struct iosys_map

	@r2@
	@@
	(
	- DMA_BUF_MAP_INIT_VADDR
	+ IOSYS_MAP_INIT_VADDR
	|
	- dma_buf_map_set_vaddr
	+ iosys_map_set_vaddr
	|
	- dma_buf_map_set_vaddr_iomem
	+ iosys_map_set_vaddr_iomem
	|
	- dma_buf_map_is_equal
	+ iosys_map_is_equal
	|
	- dma_buf_map_is_null
	+ iosys_map_is_null
	|
	- dma_buf_map_is_set
	+ iosys_map_is_set
	|
	- dma_buf_map_clear
	+ iosys_map_clear
	|
	- dma_buf_map_memcpy_to
	+ iosys_map_memcpy_to
	|
	- dma_buf_map_incr
	+ iosys_map_incr
	)

	@@
	@@
	- #include &lt;linux/dma-buf-map.h&gt;
	+ #include &lt;linux/iosys-map.h&gt;

Then some files had their includes adjusted and some comments were
update to remove mentions to dma-buf-map.

Since this is not specific to dma-buf anymore, move the documentation to
the "Bus-Independent Device Accesses" section.

v2:
  - Squash patches

v3:
  - Fix wrong removal of dma-buf.h from MAINTAINERS
  - Move documentation from dma-buf.rst to device-io.rst

v4:
  - Change documentation title and level

Signed-off-by: Lucas De Marchi &lt;lucas.demarchi@intel.com&gt;
Acked-by: Christian König &lt;christian.koenig@amd.com&gt;
Acked-by: Sumit Semwal &lt;sumit.semwal@linaro.org&gt;
Acked-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220204170541.829227-1-lucas.demarchi@intel.com
</content>
</entry>
<entry>
<title>Revert "fbcon: Disable accelerated scrolling"</title>
<updated>2022-02-02T14:15:11+00:00</updated>
<author>
<name>Helge Deller</name>
<email>deller@gmx.de</email>
</author>
<published>2022-02-02T13:55:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=87ab9f6b7417349aa197a6c7098d4fdd4beebb74'/>
<id>urn:sha1:87ab9f6b7417349aa197a6c7098d4fdd4beebb74</id>
<content type='text'>
This reverts commit 39aead8373b3c20bb5965c024dfb51a94e526151.

Revert the first (of 2) commits which disabled scrolling acceleration in
fbcon/fbdev.  It introduced a regression for fbdev-supported graphic cards
because of the performance penalty by doing screen scrolling by software
instead of using the existing graphic card 2D hardware acceleration.

Console scrolling acceleration was disabled by dropping code which
checked at runtime the driver hardware capabilities for the
BINFO_HWACCEL_COPYAREA or FBINFO_HWACCEL_FILLRECT flags and if set, it
enabled scrollmode SCROLL_MOVE which uses hardware acceleration to move
screen contents.  After dropping those checks scrollmode was hard-wired
to SCROLL_REDRAW instead, which forces all graphic cards to redraw every
character at the new screen position when scrolling.

This change effectively disabled all hardware-based scrolling acceleration for
ALL drivers, because now all kind of 2D hardware acceleration (bitblt,
fillrect) in the drivers isn't used any longer.

The original commit message mentions that only 3 DRM drivers (nouveau, omapdrm
and gma500) used hardware acceleration in the past and thus code for checking
and using scrolling acceleration is obsolete.

This statement is NOT TRUE, because beside the DRM drivers there are around 35
other fbdev drivers which depend on fbdev/fbcon and still provide hardware
acceleration for fbdev/fbcon.

The original commit message also states that syzbot found lots of bugs in fbcon
and thus it's "often the solution to just delete code and remove features".
This is true, and the bugs - which actually affected all users of fbcon,
including DRM - were fixed, or code was dropped like e.g. the support for
software scrollback in vgacon (commit 973c096f6a85).

So to further analyze which bugs were found by syzbot, I've looked through all
patches in drivers/video which were tagged with syzbot or syzkaller back to
year 2005. The vast majority fixed the reported issues on a higher level, e.g.
when screen is to be resized, or when font size is to be changed. The few ones
which touched driver code fixed a real driver bug, e.g. by adding a check.

But NONE of those patches touched code of either the SCROLL_MOVE or the
SCROLL_REDRAW case.

That means, there was no real reason why SCROLL_MOVE had to be ripped-out and
just SCROLL_REDRAW had to be used instead. The only reason I can imagine so far
was that SCROLL_MOVE wasn't used by DRM and as such it was assumed that it
could go away. That argument completely missed the fact that SCROLL_MOVE is
still heavily used by fbdev (non-DRM) drivers.

Some people mention that using memcpy() instead of the hardware acceleration is
pretty much the same speed. But that's not true, at least not for older graphic
cards and machines where we see speed decreases by factor 10 and more and thus
this change leads to console responsiveness way worse than before.

That's why the original commit is to be reverted. By reverting we
reintroduce hardware-based scrolling acceleration and fix the
performance regression for fbdev drivers.

There isn't any impact on DRM when reverting those patches.

Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Acked-by: Sven Schnelle &lt;svens@stackframe.org&gt;
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220202135531.92183-3-deller@gmx.de
</content>
</entry>
<entry>
<title>Revert "fbdev: Garbage collect fbdev scrolling acceleration, part 1 (from TODO list)"</title>
<updated>2022-02-02T14:14:56+00:00</updated>
<author>
<name>Helge Deller</name>
<email>deller@gmx.de</email>
</author>
<published>2022-02-02T13:55:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=1148836fd3226c20de841084aba24184d4fbbe77'/>
<id>urn:sha1:1148836fd3226c20de841084aba24184d4fbbe77</id>
<content type='text'>
This reverts commit b3ec8cdf457e5e63d396fe1346cc788cf7c1b578.

Revert the second (of 2) commits which disabled scrolling acceleration
in fbcon/fbdev.  It introduced a regression for fbdev-supported graphic
cards because of the performance penalty by doing screen scrolling by
software instead of using the existing graphic card 2D hardware
acceleration.

Console scrolling acceleration was disabled by dropping code which
checked at runtime the driver hardware capabilities for the
BINFO_HWACCEL_COPYAREA or FBINFO_HWACCEL_FILLRECT flags and if set, it
enabled scrollmode SCROLL_MOVE which uses hardware acceleration to move
screen contents.  After dropping those checks scrollmode was hard-wired
to SCROLL_REDRAW instead, which forces all graphic cards to redraw every
character at the new screen position when scrolling.

This change effectively disabled all hardware-based scrolling acceleration for
ALL drivers, because now all kind of 2D hardware acceleration (bitblt,
fillrect) in the drivers isn't used any longer.

The original commit message mentions that only 3 DRM drivers (nouveau, omapdrm
and gma500) used hardware acceleration in the past and thus code for checking
and using scrolling acceleration is obsolete.

This statement is NOT TRUE, because beside the DRM drivers there are around 35
other fbdev drivers which depend on fbdev/fbcon and still provide hardware
acceleration for fbdev/fbcon.

The original commit message also states that syzbot found lots of bugs in fbcon
and thus it's "often the solution to just delete code and remove features".
This is true, and the bugs - which actually affected all users of fbcon,
including DRM - were fixed, or code was dropped like e.g. the support for
software scrollback in vgacon (commit 973c096f6a85).

So to further analyze which bugs were found by syzbot, I've looked through all
patches in drivers/video which were tagged with syzbot or syzkaller back to
year 2005. The vast majority fixed the reported issues on a higher level, e.g.
when screen is to be resized, or when font size is to be changed. The few ones
which touched driver code fixed a real driver bug, e.g. by adding a check.

But NONE of those patches touched code of either the SCROLL_MOVE or the
SCROLL_REDRAW case.

That means, there was no real reason why SCROLL_MOVE had to be ripped-out and
just SCROLL_REDRAW had to be used instead. The only reason I can imagine so far
was that SCROLL_MOVE wasn't used by DRM and as such it was assumed that it
could go away. That argument completely missed the fact that SCROLL_MOVE is
still heavily used by fbdev (non-DRM) drivers.

Some people mention that using memcpy() instead of the hardware acceleration is
pretty much the same speed. But that's not true, at least not for older graphic
cards and machines where we see speed decreases by factor 10 and more and thus
this change leads to console responsiveness way worse than before.

That's why the original commit is to be reverted. By reverting we
reintroduce hardware-based scrolling acceleration and fix the
performance regression for fbdev drivers.

There isn't any impact on DRM when reverting those patches.

Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Acked-by: Sven Schnelle &lt;svens@stackframe.org&gt;
Cc: stable@vger.kernel.org # v5.16+
Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220202135531.92183-2-deller@gmx.de
</content>
</entry>
<entry>
<title>drm: Add TODO item for requesting memory regions</title>
<updated>2022-01-27T08:21:14+00:00</updated>
<author>
<name>Thomas Zimmermann</name>
<email>tzimmermann@suse.de</email>
</author>
<published>2022-01-25T09:12:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=bb7eb3b19f198b704feb13cc38067db4104961a4'/>
<id>urn:sha1:bb7eb3b19f198b704feb13cc38067db4104961a4</id>
<content type='text'>
Add a TODO item about requesting  memory regions for each driver. The
current DRM drivers don't do this consistently.

Signed-off-by: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Reviewed-by: Javier Martinez Canillas &lt;javierm@redhat.com&gt;
Reviewed-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220125091222.21457-6-tzimmermann@suse.de
</content>
</entry>
</feed>
