On Mon, Oct 12, 2026 at 04:44:06PM +0800, Yongxing Mou wrote:
>
>
> On 10/1/2026 6:32 PM, Dmitry Baryshkov wrote:
> > On Tue, Sep 29, 2026 at 12:25:32PM +0800, Yongxing Mou wrote:
> > > From: Abhinav Kumar <[email protected]>
> > >
> > > Whenever virtual channel slot allocation changes, the DP
> > > source must send the action control trigger sequence to notify
> > > the sink about the same. This would be applicable during the
> > > start and stop of the pixel stream. Add the infrastructure
> > > to be able to send ACT packets for the DP controller when
> > > operating in MST mode.
> > >
> > > Add REG_DP_MST_ACT, the ACT trigger register used by this sequence.
> > >
> > > Signed-off-by: Abhinav Kumar <[email protected]>
> > > Signed-off-by: Yongxing Mou <[email protected]>
> > > ---
> > > drivers/gpu/drm/msm/dp/dp_ctrl.c | 44
> > > ++++++++++++++++++++++++++++++++++++-
> > > drivers/gpu/drm/msm/dp/dp_ctrl.h | 5 ++++-
> > > drivers/gpu/drm/msm/dp/dp_display.c | 3 ++-
> > > drivers/gpu/drm/msm/dp/dp_display.h | 1 +
> > > drivers/gpu/drm/msm/dp/dp_reg.h | 1 +
> > > 5 files changed, 51 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > index e1614bc49a7c..65d22505c2b6 100644
> > > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > > @@ -142,6 +142,7 @@ struct msm_dp_ctrl_private {
> > > bool core_clks_on;
> > > bool link_clks_on;
> > > bool stream_clks_on[DP_STREAM_MAX];
> > > + bool mst_active;
> >
> > I really don't like the idea of having this flag in two locations. Here
> > and in the msm_dp_display_private. Can we have it in one place only?
> >
> These two fields are intended to represent different states with different
> lifetimes.
>
> msm_dp::mst_active tracks whether the DP connection has an active MST
> session. The controller field records whether the current controller/link is
> operating in MST mode and remains valid until the link is shut down.
>
> I agree that using mst_active for both fields makes them look like
> duplicated state. I propose renaming the controller field to mst_mode while
> keeping the display-side field as mst_active.
>
> Would you agree with this change?
What is the difference between these two? I.e. what os the difference
between those two?
> > > };
> >
> > [...]
> >
> > > static void msm_dp_display_unprepare(struct msm_dp_display_private *dp)
> > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.h
> > > b/drivers/gpu/drm/msm/dp/dp_display.h
> > > index 83117e7619f3..472429d09200 100644
> > > --- a/drivers/gpu/drm/msm/dp/dp_display.h
> > > +++ b/drivers/gpu/drm/msm/dp/dp_display.h
> > > @@ -19,6 +19,7 @@ struct msm_dp {
> > > struct drm_bridge *bridge;
> > > bool audio_enabled;
> > > bool power_on;
> > > + bool mst_active;
> > > unsigned int connector_type;
> > > bool is_edp;
> >
>
--
With best wishes
Dmitry
