Re: [PATCH v2 04/10] drm/amd/display: use eld_mutex to protect access to connector->eld

[Harry Wentland <harry.wentland@amd.com>]

On 2024-12-16 10:31, Alex Deucher wrote:
> On Mon, Dec 16, 2024 at 10:12 AM Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
>>
>> On Mon, 16 Dec 2024 at 16:53, Harry Wentland <harry.wentland@amd.com> wrote:
>>>
>>>
>>>
>>> On 2024-12-10 16:20, Dmitry Baryshkov wrote:
>>>> On Fri, Dec 06, 2024 at 11:43:07AM +0200, Dmitry Baryshkov wrote:
>>>>> Reading access to connector->eld can happen at the same time the
>>>>> drm_edid_to_eld() updates the data. Take the newly added eld_mutex in
>>>>> order to protect connector->eld from concurrent access.
>>>>>
>>>>> Reviewed-by: Maxime Ripard <mripard@kernel.org>
>>>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>>>> ---
>>>>>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 ++
>>>>>  1 file changed, 2 insertions(+)
>>>>
>>>> Harry, Leo, Rodrigo, Alex, Christian, Xinhui, any response to this one
>>>> and to the radeon patches? I'd like to be able to pick the series for
>>>> drm-misc and these two are not reviewed by you.
>>>>
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>>> index 19a58630e774029767bf2a27eb4ddf17e3c21129..04c68c320252b5ce9647f0606fb86fe57f347639 100644
>>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>>> @@ -1037,8 +1037,10 @@ static int amdgpu_dm_audio_component_get_eld(struct device *kdev, int port,
>>>>>                      continue;
>>>>>
>>>>>              *enabled = true;
>>>>> +            mutex_lock(&connector->eld_mutex);
>>>>>              ret = drm_eld_size(connector->eld);
>>>>>              memcpy(buf, connector->eld, min(max_bytes, ret));
>>>>> +            mutex_unlock(&connector->eld_mutex);
>>>
>>> All of this is wrapped by the adev->dm.audio_lock mutex. It might
>>> be safer to modify the audio_lock mutex so it only guards the
>>> aconnector->audio_inst access.
>>>
>>> But I don't see any way these mutexes would otherwise interact,
>>> so this change should be good as-is.
>>>
>>> Reviewed-by: Harry Wentland <harry.wentland@amd.com>
>>
>> Would you ack it to merge it through drm-misc? Or would you prefer to
>> pick up those two patches after merging drm-misc-next once the rest of
>> the series lands?
> 
> Merging through drm-misc is fine with me.
> 

Same.

Harry

> Thanks,
> 
> Alex
> 
>>
>>>
>>> Harry
>>>
>>>>>
>>>>>              break;
>>>>>      }
>>>>>
>>>>> --
>>>>> 2.39.5
>>>>>
>>>>
>>>
>>
>>
>> --
>> With best wishes
>> Dmitry