<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c, branch v6.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drm/amdgpu/display/mst: limit payload to be updated one by one</title>
<updated>2023-01-25T18:54:05+00:00</updated>
<author>
<name>Wayne Lin</name>
<email>Wayne.Lin@amd.com</email>
</author>
<published>2022-12-09T11:05:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cb1e0b015f56b8f3c7f5ce33ff4b782ee5674512'/>
<id>cb1e0b015f56b8f3c7f5ce33ff4b782ee5674512</id>
<content type='text'>
[Why]
amdgpu expects to update payload table for one stream one time
by calling dm_helpers_dp_mst_write_payload_allocation_table().
Currently, it get modified to try to update HW payload table
at once by referring mst_state.

[How]
This is just a quick workaround. Should find way to remove the
temporary struct dc_dp_mst_stream_allocation_table later if set
struct link_mst_stream_allocatio directly is possible.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2171
Signed-off-by: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Signed-off-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Fixes: 4d07b0bc4034 ("drm/display/dp_mst: Move all payload info into the atomic state")
Cc: stable@vger.kernel.org # 6.1
Acked-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Tested-by: Didier Raboud &lt;odyx@debian.org&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[Why]
amdgpu expects to update payload table for one stream one time
by calling dm_helpers_dp_mst_write_payload_allocation_table().
Currently, it get modified to try to update HW payload table
at once by referring mst_state.

[How]
This is just a quick workaround. Should find way to remove the
temporary struct dc_dp_mst_stream_allocation_table later if set
struct link_mst_stream_allocatio directly is possible.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2171
Signed-off-by: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Signed-off-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Fixes: 4d07b0bc4034 ("drm/display/dp_mst: Move all payload info into the atomic state")
Cc: stable@vger.kernel.org # 6.1
Acked-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Tested-by: Didier Raboud &lt;odyx@debian.org&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Fix race condition in DPIA AUX transfer</title>
<updated>2022-11-29T16:03:38+00:00</updated>
<author>
<name>Stylon Wang</name>
<email>stylon.wang@amd.com</email>
</author>
<published>2022-11-10T13:53:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ead08b95fa50f40618c72b93a849c4ae30c9cd50'/>
<id>ead08b95fa50f40618c72b93a849c4ae30c9cd50</id>
<content type='text'>
[Why]
This fix was intended for improving on coding style but in the process
uncovers a race condition, which explains why we are getting incorrect
length in DPIA AUX replies. Due to the call path of DPIA AUX going from
DC back to DM layer then again into DC and the added complexities on top
of current DC AUX implementation, a proper fix to rely on current dc_lock
to address the race condition is difficult without a major overhual
on how DPIA AUX is implemented.

[How]
- Add a mutex dpia_aux_lock to protect DPIA AUX transfers
- Remove DMUB_ASYNC_TO_SYNC_ACCESS_* codes and rely solely on
  aux_return_code_type for error reporting and handling
- Separate SET_CONFIG from DPIA AUX transfer because they have quiet
  different processing logic
- Remove unnecessary type casting to and from void * type

Reviewed-by: Nicholas Kazlauskas &lt;Nicholas.Kazlauskas@amd.com&gt;
Acked-by: Jasdeep Dhillon &lt;jdhillon@amd.com&gt;
Signed-off-by: Stylon Wang &lt;stylon.wang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[Why]
This fix was intended for improving on coding style but in the process
uncovers a race condition, which explains why we are getting incorrect
length in DPIA AUX replies. Due to the call path of DPIA AUX going from
DC back to DM layer then again into DC and the added complexities on top
of current DC AUX implementation, a proper fix to rely on current dc_lock
to address the race condition is difficult without a major overhual
on how DPIA AUX is implemented.

[How]
- Add a mutex dpia_aux_lock to protect DPIA AUX transfers
- Remove DMUB_ASYNC_TO_SYNC_ACCESS_* codes and rely solely on
  aux_return_code_type for error reporting and handling
- Separate SET_CONFIG from DPIA AUX transfer because they have quiet
  different processing logic
- Remove unnecessary type casting to and from void * type

Reviewed-by: Nicholas Kazlauskas &lt;Nicholas.Kazlauskas@amd.com&gt;
Acked-by: Jasdeep Dhillon &lt;jdhillon@amd.com&gt;
Signed-off-by: Stylon Wang &lt;stylon.wang@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Only update link settings after successful MST link train</title>
<updated>2022-11-09T22:41:41+00:00</updated>
<author>
<name>Michael Strauss</name>
<email>michael.strauss@amd.com</email>
</author>
<published>2022-10-20T19:57:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ea192af507d99014775a757bbdb5f6e487fc6c7a'/>
<id>ea192af507d99014775a757bbdb5f6e487fc6c7a</id>
<content type='text'>
[WHY]
Currently driver reduces verified link caps on DPIA devices if a link is
trained at a link rate below the max rate verified during link detection.
This blocks high bandwidth modes after setting a low bandwidth mode.

[HOW]
Only update link rate after a successful link train if link is MST.

Reviewed-by: Mustapha Ghaddar &lt;Mustapha.Ghaddar@amd.com&gt;
Acked-by: Alan Liu &lt;HaoPing.Liu@amd.com&gt;
Signed-off-by: Michael Strauss &lt;michael.strauss@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[WHY]
Currently driver reduces verified link caps on DPIA devices if a link is
trained at a link rate below the max rate verified during link detection.
This blocks high bandwidth modes after setting a low bandwidth mode.

[HOW]
Only update link rate after a successful link train if link is MST.

Reviewed-by: Mustapha Ghaddar &lt;Mustapha.Ghaddar@amd.com&gt;
Acked-by: Alan Liu &lt;HaoPing.Liu@amd.com&gt;
Signed-off-by: Michael Strauss &lt;michael.strauss@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "drm/amd/display: Limit max DSC target bpp for specific monitors"</title>
<updated>2022-10-27T19:12:09+00:00</updated>
<author>
<name>Hamza Mahfooz</name>
<email>hamza.mahfooz@amd.com</email>
</author>
<published>2022-10-25T19:04:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6803dfd3a69ccb318772463a86e40929fd4fbac7'/>
<id>6803dfd3a69ccb318772463a86e40929fd4fbac7</id>
<content type='text'>
This reverts commit 55eea8ef98641f6e1e1c202bd3a49a57c1dd4059.

This quirk is now handled in the DRM core, so we can drop all of
the internal code that was added to handle it.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Hamza Mahfooz &lt;hamza.mahfooz@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 55eea8ef98641f6e1e1c202bd3a49a57c1dd4059.

This quirk is now handled in the DRM core, so we can drop all of
the internal code that was added to handle it.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Hamza Mahfooz &lt;hamza.mahfooz@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Refactor edp panel power sequencer(PPS) codes</title>
<updated>2022-09-19T19:13:08+00:00</updated>
<author>
<name>Ian Chen</name>
<email>ian.chen@amd.com</email>
</author>
<published>2022-08-30T06:50:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eccff6cdde6f47dcd88fca8c638e0d651f0e09f8'/>
<id>eccff6cdde6f47dcd88fca8c638e0d651f0e09f8</id>
<content type='text'>
[Why &amp; How]
Move extra panel power sequencer settings into panel_cofig struct.

Reviewed-by: Anthony Koo &lt;Anthony.Koo@amd.com&gt;
Acked-by: Wayne Lin &lt;wayne.lin@amd.com&gt;
Signed-off-by: Ian Chen &lt;ian.chen@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[Why &amp; How]
Move extra panel power sequencer settings into panel_cofig struct.

Reviewed-by: Anthony Koo &lt;Anthony.Koo@amd.com&gt;
Acked-by: Wayne Lin &lt;wayne.lin@amd.com&gt;
Signed-off-by: Ian Chen &lt;ian.chen@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'amd-drm-next-6.1-2022-09-08' of https://gitlab.freedesktop.org/agd5f/linux into drm-next</title>
<updated>2022-09-12T09:17:41+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2022-09-12T09:17:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=47519d8224babc9dee489ea96dfeac726fe544cc'/>
<id>47519d8224babc9dee489ea96dfeac726fe544cc</id>
<content type='text'>
amd-drm-next-6.1-2022-09-08:

amdgpu:
- Mode2 reset for RDNA2
- Lots of new DC documentation
- Add documentation about different asic families
- DSC improvements
- Aldebaran fixes
- Misc spelling and grammar fixes
- GFXOFF stats support for vangogh
- DC frame size fixes
- NBIO 7.7 updates
- DCN 3.2 updates
- DCN 3.1.4 Updates
- SMU 13.x updates
- Misc bug fixes
- Rework DC register offset handling
- GC 11.x updates
- PSP 13.x updates
- SDMA 6.x updates
- GMC 11.x updates
- SR-IOV updates
- PSP fixes for TA unloading
- DSC passthrough support
- Misc code cleanups

amdkfd:
- ISA fixes for some GC 10.3 IPs
- Misc code cleanups

radeon:
- Delayed work flush fix
- Use time_after for some jiffies calculations

drm:
- DSC passthrough aux support

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
From: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220908155202.57862-1-alexander.deucher@amd.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
amd-drm-next-6.1-2022-09-08:

amdgpu:
- Mode2 reset for RDNA2
- Lots of new DC documentation
- Add documentation about different asic families
- DSC improvements
- Aldebaran fixes
- Misc spelling and grammar fixes
- GFXOFF stats support for vangogh
- DC frame size fixes
- NBIO 7.7 updates
- DCN 3.2 updates
- DCN 3.1.4 Updates
- SMU 13.x updates
- Misc bug fixes
- Rework DC register offset handling
- GC 11.x updates
- PSP 13.x updates
- SDMA 6.x updates
- GMC 11.x updates
- SR-IOV updates
- PSP fixes for TA unloading
- DSC passthrough support
- Misc code cleanups

amdkfd:
- ISA fixes for some GC 10.3 IPs
- Misc code cleanups

radeon:
- Delayed work flush fix
- Use time_after for some jiffies calculations

drm:
- DSC passthrough aux support

Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
From: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220908155202.57862-1-alexander.deucher@amd.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'drm-misc-next-2022-09-09' of git://anongit.freedesktop.org/drm/drm-misc into drm-next</title>
<updated>2022-09-11T12:03:07+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2022-09-11T11:46:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fb34d8a04e5876552cd0d4f9e14400ee13f116fb'/>
<id>fb34d8a04e5876552cd0d4f9e14400ee13f116fb</id>
<content type='text'>
drm-misc-next for v6.1-rc1:

[airlied - fix sun4i_tv build]

UAPI Changes:
- Hide unregistered connectors from GETCONNECTOR ioctl.
- drm/virtio no longer advertises LINEAR modifier, as it doesn't work.
-

Cross-subsystem Changes:
- Fix GPF in udmabuf failure path.

Core Changes:
- Rework TTM placement to use intersect/compatible functions.
- Drop legacy DP-MST support.
- More DP-MST related fixes, and move all state into atomic.
- Make DRM_MIPI_DBI select DRM_KMS_HELPER.
- Add audio_infoframe packing for DP.
- Add logging when some atomic check functions fail.
- Assorted documentation updates and fixes.

Driver Changes:
- Assorted cleanups and fixes in msm, lcdif, nouveau, virtio,
  panel/ilitek, bridge/icn6211, tve200, gma500, bridge/*, panfrost, via,
  bochs, qxl, sun4i.
- Add add AUO B133UAN02.1, IVO M133NW4J-R3, Innolux N120ACA-EA1 eDP panels.
- Improve DP-MST modeset state handling in amdgpu, nouveau, i915.
- Drop DP-MST from radeon driver, it was broken and only user of legacy
  DP-MST.
- Handle unplugging better in vc4.
- Simplify drm cmdparser tests.
- Add DP support to ti-sn65dsi86.
- Add MT8195 DP support to mediatek.
- Support RGB565, XRGB64, and ARGB64 formats in vkms.
- Convert sun4i tv support to atomic.
- Refactor vc4/vec TV Modesetting, and fix timings.
- Use atomic helpers instead of simple display helpers in ssd130x.

Maintainer changes:
- Add Douglas Anderson as reviewer for panel-edp.

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/a489485b-3ebc-c734-0f80-aed963d89efe@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
drm-misc-next for v6.1-rc1:

[airlied - fix sun4i_tv build]

UAPI Changes:
- Hide unregistered connectors from GETCONNECTOR ioctl.
- drm/virtio no longer advertises LINEAR modifier, as it doesn't work.
-

Cross-subsystem Changes:
- Fix GPF in udmabuf failure path.

Core Changes:
- Rework TTM placement to use intersect/compatible functions.
- Drop legacy DP-MST support.
- More DP-MST related fixes, and move all state into atomic.
- Make DRM_MIPI_DBI select DRM_KMS_HELPER.
- Add audio_infoframe packing for DP.
- Add logging when some atomic check functions fail.
- Assorted documentation updates and fixes.

Driver Changes:
- Assorted cleanups and fixes in msm, lcdif, nouveau, virtio,
  panel/ilitek, bridge/icn6211, tve200, gma500, bridge/*, panfrost, via,
  bochs, qxl, sun4i.
- Add add AUO B133UAN02.1, IVO M133NW4J-R3, Innolux N120ACA-EA1 eDP panels.
- Improve DP-MST modeset state handling in amdgpu, nouveau, i915.
- Drop DP-MST from radeon driver, it was broken and only user of legacy
  DP-MST.
- Handle unplugging better in vc4.
- Simplify drm cmdparser tests.
- Add DP support to ti-sn65dsi86.
- Add MT8195 DP support to mediatek.
- Support RGB565, XRGB64, and ARGB64 formats in vkms.
- Convert sun4i tv support to atomic.
- Refactor vc4/vec TV Modesetting, and fix timings.
- Use atomic helpers instead of simple display helpers in ssd130x.

Maintainer changes:
- Add Douglas Anderson as reviewer for panel-edp.

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/a489485b-3ebc-c734-0f80-aed963d89efe@linux.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Refactor edp dsc codes.</title>
<updated>2022-08-29T21:58:47+00:00</updated>
<author>
<name>Ian Chen</name>
<email>ian.chen@amd.com</email>
</author>
<published>2022-08-04T07:44:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c17a34e0526fafc0e1e7f707c634d7e49dd08197'/>
<id>c17a34e0526fafc0e1e7f707c634d7e49dd08197</id>
<content type='text'>
Refactor edp dsc codes.

We split out edp dsc config from "global" to "per-panel" config settings.

Reviewed-by: Mike Hsieh &lt;mike.hsieh@amd.com&gt;
Acked-by: Brian Chang &lt;Brian.Chang@amd.com&gt;
Signed-off-by: Ian Chen &lt;ian.chen@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Refactor edp dsc codes.

We split out edp dsc config from "global" to "per-panel" config settings.

Reviewed-by: Mike Hsieh &lt;mike.hsieh@amd.com&gt;
Acked-by: Brian Chang &lt;Brian.Chang@amd.com&gt;
Signed-off-by: Ian Chen &lt;ian.chen@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/display/dp_mst: Move all payload info into the atomic state</title>
<updated>2022-08-23T20:54:09+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2022-08-17T19:38:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4d07b0bc403403438d9cf88450506240c5faf92f'/>
<id>4d07b0bc403403438d9cf88450506240c5faf92f</id>
<content type='text'>
Now that we've finally gotten rid of the non-atomic MST users leftover in
the kernel, we can finally get rid of all of the legacy payload code we
have and move as much as possible into the MST atomic state structs. The
main purpose of this is to make the MST code a lot less confusing to work
on, as there's a lot of duplicated logic that doesn't really need to be
here. As well, this should make introducing features like fallback link
retraining and DSC support far easier.

Since the old payload code was pretty gnarly and there's a Lot of changes
here, I expect this might be a bit difficult to review. So to make things
as easy as possible for reviewers, I'll sum up how both the old and new
code worked here (it took me a while to figure this out too!).

The old MST code basically worked by maintaining two different payload
tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
modified payload we wanted to push to the topology, while payloads held the
payload table that was currently programmed in hardware. Modifications to
proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then, they
would be pushed via drm_dp_mst_update_payload_step1() and
drm_dp_mst_update_payload_step2().

Furthermore, it's important to note how adding and removing VC payloads
actually worked with drm_dp_mst_update_payload_step1(). When a VC payload
is removed from the VC table, all VC payloads which come after the removed
VC payload's slots must have their time slots shifted towards the start of
the table. The old code handles this by looping through the entire payload
table and recomputing the start slot for every payload in the topology from
scratch. While very much overkill, this ends up doing the right thing
because we always order the VCPIs for payloads from first to last starting
timeslot.

It's important to also note that drm_dp_mst_update_payload_step2() isn't
actually limited to updating a single payload - the driver can use it to
queue up multiple payload changes so that as many of them can be sent as
possible before waiting for the ACT. This is -technically- not against
spec, but as Wayne Lin has pointed out it's not consistently implemented
correctly in hubs - so it might as well be.

drm_dp_mst_update_payload_step2() is pretty self explanatory and basically
the same between the old and new code, save for the fact we don't have a
second step for deleting payloads anymore -and thus rename it to
drm_dp_mst_add_payload_step2().

The new payload code stores all of the current payload info within the MST
atomic state and computes as much of the state as possible ahead of time.
This has the one exception of the starting timeslots for payloads, which
can't be determined at atomic check time since the starting time slots will
vary depending on what order CRTCs are enabled in the atomic state - which
varies from driver to driver. These are still stored in the atomic MST
state, but are only copied from the old MST state during atomic commit
time. Likewise, this is when new start slots are determined.

Adding/removing payloads now works much more closely to how things are
described in the spec. When we delete a payload, we loop through the
current list of payloads and update the start slots for any payloads whose
time slots came after the payload we just deleted. Determining the starting
time slots for new payloads being added is done by simply keeping track of
where the end of the VC table is in
drm_dp_mst_topology_mgr-&gt;next_start_slot. Additionally, it's worth noting
that we no longer have a single update_payload() function. Instead, we now
have drm_dp_mst_add_payload_step1|2() and drm_dp_mst_remove_payload(). As
such, it's now left it up to the driver to figure out when to add or remove
payloads. The driver already knows when it's disabling/enabling CRTCs, so
it also already knows when payloads should be added or removed.

Changes since v1:
* Refactor around all of the completely dead code changes that are
  happening in amdgpu for some reason when they really shouldn't even be
  there in the first place… :\
* Remove mention of sending one ACT per series of payload updates. As Wayne
  Lin pointed out, there are apparently hubs on the market that don't work
  correctly with this scheme and require a separate ACT per payload update.
* Fix accidental drop of mst_mgr.lock - Wayne Lin
* Remove mentions of allowing multiple ACT updates per payload change,
  mention that this is a result of vendors not consistently supporting this
  part of the spec and requiring a unique ACT for each payload change.
* Get rid of reference to drm_dp_mst_port in DC - turns out I just got
  myself confused by DC and we don't actually need this.
Changes since v2:
* Get rid of fix for not sending payload deallocations if ddps=0 and just
  go back to wayne's fix

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Fangzhi Zuo &lt;Jerry.Zuo@amd.com&gt;
Cc: Jani Nikula &lt;jani.nikula@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Sean Paul &lt;sean@poorly.run&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-18-lyude@redhat.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that we've finally gotten rid of the non-atomic MST users leftover in
the kernel, we can finally get rid of all of the legacy payload code we
have and move as much as possible into the MST atomic state structs. The
main purpose of this is to make the MST code a lot less confusing to work
on, as there's a lot of duplicated logic that doesn't really need to be
here. As well, this should make introducing features like fallback link
retraining and DSC support far easier.

Since the old payload code was pretty gnarly and there's a Lot of changes
here, I expect this might be a bit difficult to review. So to make things
as easy as possible for reviewers, I'll sum up how both the old and new
code worked here (it took me a while to figure this out too!).

The old MST code basically worked by maintaining two different payload
tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
modified payload we wanted to push to the topology, while payloads held the
payload table that was currently programmed in hardware. Modifications to
proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then, they
would be pushed via drm_dp_mst_update_payload_step1() and
drm_dp_mst_update_payload_step2().

Furthermore, it's important to note how adding and removing VC payloads
actually worked with drm_dp_mst_update_payload_step1(). When a VC payload
is removed from the VC table, all VC payloads which come after the removed
VC payload's slots must have their time slots shifted towards the start of
the table. The old code handles this by looping through the entire payload
table and recomputing the start slot for every payload in the topology from
scratch. While very much overkill, this ends up doing the right thing
because we always order the VCPIs for payloads from first to last starting
timeslot.

It's important to also note that drm_dp_mst_update_payload_step2() isn't
actually limited to updating a single payload - the driver can use it to
queue up multiple payload changes so that as many of them can be sent as
possible before waiting for the ACT. This is -technically- not against
spec, but as Wayne Lin has pointed out it's not consistently implemented
correctly in hubs - so it might as well be.

drm_dp_mst_update_payload_step2() is pretty self explanatory and basically
the same between the old and new code, save for the fact we don't have a
second step for deleting payloads anymore -and thus rename it to
drm_dp_mst_add_payload_step2().

The new payload code stores all of the current payload info within the MST
atomic state and computes as much of the state as possible ahead of time.
This has the one exception of the starting timeslots for payloads, which
can't be determined at atomic check time since the starting time slots will
vary depending on what order CRTCs are enabled in the atomic state - which
varies from driver to driver. These are still stored in the atomic MST
state, but are only copied from the old MST state during atomic commit
time. Likewise, this is when new start slots are determined.

Adding/removing payloads now works much more closely to how things are
described in the spec. When we delete a payload, we loop through the
current list of payloads and update the start slots for any payloads whose
time slots came after the payload we just deleted. Determining the starting
time slots for new payloads being added is done by simply keeping track of
where the end of the VC table is in
drm_dp_mst_topology_mgr-&gt;next_start_slot. Additionally, it's worth noting
that we no longer have a single update_payload() function. Instead, we now
have drm_dp_mst_add_payload_step1|2() and drm_dp_mst_remove_payload(). As
such, it's now left it up to the driver to figure out when to add or remove
payloads. The driver already knows when it's disabling/enabling CRTCs, so
it also already knows when payloads should be added or removed.

Changes since v1:
* Refactor around all of the completely dead code changes that are
  happening in amdgpu for some reason when they really shouldn't even be
  there in the first place… :\
* Remove mention of sending one ACT per series of payload updates. As Wayne
  Lin pointed out, there are apparently hubs on the market that don't work
  correctly with this scheme and require a separate ACT per payload update.
* Fix accidental drop of mst_mgr.lock - Wayne Lin
* Remove mentions of allowing multiple ACT updates per payload change,
  mention that this is a result of vendors not consistently supporting this
  part of the spec and requiring a unique ACT for each payload change.
* Get rid of reference to drm_dp_mst_port in DC - turns out I just got
  myself confused by DC and we don't actually need this.
Changes since v2:
* Get rid of fix for not sending payload deallocations if ddps=0 and just
  go back to wayne's fix

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Fangzhi Zuo &lt;Jerry.Zuo@amd.com&gt;
Cc: Jani Nikula &lt;jani.nikula@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Sean Paul &lt;sean@poorly.run&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-18-lyude@redhat.com
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/dm/mst: Rename get_payload_table()</title>
<updated>2022-08-23T20:53:34+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2022-08-17T19:38:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dbaadb3cebaad49c37e3fec937e73e6e41054404'/>
<id>dbaadb3cebaad49c37e3fec937e73e6e41054404</id>
<content type='text'>
This function isn't too confusing if you see the comment around the
call-site for it, but if you don't then it's not at all obvious this is
meant to copy DRM's payload table over to DC's internal state structs.
Seeing this function before finding that comment definitely threw me into a
loop a few times.

So, let's rename this to make it's purpose more obvious regardless of where
in the code you are.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Fangzhi Zuo &lt;Jerry.Zuo@amd.com&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-3-lyude@redhat.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This function isn't too confusing if you see the comment around the
call-site for it, but if you don't then it's not at all obvious this is
meant to copy DRM's payload table over to DC's internal state structs.
Seeing this function before finding that comment definitely threw me into a
loop a few times.

So, let's rename this to make it's purpose more obvious regardless of where
in the code you are.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: Wayne Lin &lt;Wayne.Lin@amd.com&gt;
Cc: Fangzhi Zuo &lt;Jerry.Zuo@amd.com&gt;
Acked-by: Jani Nikula &lt;jani.nikula@intel.com&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-3-lyude@redhat.com
</pre>
</div>
</content>
</entry>
</feed>
