diff mbox series

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

Message ID 20241206-drm-connector-eld-mutex-v2-4-c9bce1ee8bea@linaro.org
State New
Headers show
Series drm/connector: add eld_mutex to protect connector->eld | expand

Commit Message

Dmitry Baryshkov Dec. 6, 2024, 9:43 a.m. UTC 
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(+)

Comments

Dmitry Baryshkov Dec. 16, 2024, 3:12 p.m. UTC | #1 
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?

>
> Harry
>
> >>
> >>              break;
> >>      }
> >>
> >> --
> >> 2.39.5
> >>
> >
>
Alex Deucher Dec. 16, 2024, 3:31 p.m. UTC | #2 
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.

Thanks,

Alex

>
> >
> > Harry
> >
> > >>
> > >>              break;
> > >>      }
> > >>
> > >> --
> > >> 2.39.5
> > >>
> > >
> >
>
>
> --
> With best wishes
> Dmitry
diff mbox series

Patch

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);
 
 		break;
 	}