[PATCH] Revert "drm/amd/display: limit clear_update_flags to dcn32 and above"
Limonciello, Mario
Mario.Limonciello at amd.com
Thu Jul 17 16:58:08 UTC 2025
On 7/17/25 11:55 AM, Melissa Wen wrote:
> On 17-07-2025 13:39, Limonciello, Mario wrote:
>> On 7/17/25 9:36 AM, Melissa Wen wrote:
>>> This reverts commit e1bd5e0bb4ca0d633ad698abd3658f8265009b81.
>>>
>>> The commit causes a regression in Steam Deck (DCN 3.01), reintroducing a
>>> functional issue reported in [1] that was fixed by calling the
>>> clear_update_flags() from commit 7671f62c10f2a.
>>>
>>> On Steam Deck, we use multiple hw plane color caps and up to two overlay
>>> planes with dynamic pipe split policy. I.e. with 1 primary + 1 overlay,
>>> the driver split planes into two (with 4 pipes), but with 1 primary + 2
>>> overlays, we don't have enough pipe for splitting. Glitches appear in
>>> this pipe-split transition of 1-2 overlay planes, if the driver doesn't
>>> clear update flags.
>>>
>>> Besides that, the issue the commit e1bd5e0bb4ca tries to address [2]
>>> isn't functional.
>>>
>>> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3441 [1]
>>> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/4129 [2]
>>> Signed-off-by: Melissa Wen <mwen at igalia.com>
>>
>> Can you please double check the use case that prompted
>> e1bd5e0bb4ca0d633ad698abd3658f8265009b81 in the first place? IE With
>> this revert you proposed do you see a traceback on unplug of external
>> display?
>
> Hi Mario,
>
> I don't see either traceback or REG_WAIT timeout when unplugging an
> external HDMI-connected display.
> I tried with the Deck Dock and USB-C to HDMI adapter. Not sure if there
> is a very specific scenario that triggers this that I didn't cover.
No; it's quite a general problem and easy to reproduce. This makes me
wonder if there should be an exception carved out for Steam Deck instead.
>
> The only message on dmesg from this action is:
> amdgpu 0000:04:00.0: amdgpu: pp_od_clk_voltage is not accessible if
> power_dpm_force_performance_level is not in manual mode!
>
> Moreover, if I move to the Desktop mode (KDE), there is no message.
>
> Melissa
>
>>
>>> ---
>>> drivers/gpu/drm/amd/display/dc/core/dc.c | 5 +++--
>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
>>> index c31f7f8e409f..7c48f72e5917 100644
>>> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
>>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
>>> @@ -5443,7 +5443,8 @@ bool dc_update_planes_and_stream(struct dc *dc,
>>> else
>>> ret = update_planes_and_stream_v2(dc, srf_updates,
>>> surface_count, stream, stream_update);
>>> - if (ret && dc->ctx->dce_version >= DCN_VERSION_3_2)
>>> +
>>> + if (ret)
>>> clear_update_flags(srf_updates, surface_count, stream);
>>>
>>> return ret;
>>> @@ -5474,7 +5475,7 @@ void dc_commit_updates_for_stream(struct dc *dc,
>>> ret = update_planes_and_stream_v1(dc, srf_updates, surface_count, stream,
>>> stream_update, state);
>>>
>>> - if (ret && dc->ctx->dce_version >= DCN_VERSION_3_2)
>>> + if (ret)
>>> clear_update_flags(srf_updates, surface_count, stream);
>>> }
>>>
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