Re: [PATCH v3 27/38] drm/msm/dp: add dp_display_get_panel() to initialize DP panel

[Yongxing Mou]

On 8/27/2025 12:33 AM, Dmitry Baryshkov wrote:
> On Mon, Aug 25, 2025 at 10:16:13PM +0800, Yongxing Mou wrote:
> > From: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> >
> > Add an API dp_display_get_panel() to initialize and return a DP
> > panel to be used by DP MST module. Since some of the fields of
> > DP panel are private, dp_display module needs to initialize these
> > parts and return the panel back.
> >
> > Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> > Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_display.c | 23 +++++++++++++++++++++++
> >   drivers/gpu/drm/msm/dp/dp_display.h |  2 ++
> >   2 files changed, 25 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> > index 84df34306fb557341bea288ea8c13b0c81b11919..abcab3ed43b6da5ef898355cf9b7561cd9fe0404 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > @@ -632,6 +632,29 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp, u32 data)
> >   	return 0;
> >   }
> >   
> > +struct msm_dp_panel *msm_dp_display_get_panel(struct msm_dp *msm_dp_display)
> > +{
> > +	struct msm_dp_display_private *dp;
> > +	struct msm_dp_panel *dp_panel;
> > +
> > +	dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
> > +
> > +	dp_panel = msm_dp_panel_get(&dp->msm_dp_display.pdev->dev, dp->aux, dp->link,
> > +			       dp->link_base, dp->mst2link_base, dp->mst3link_base,
> > +			       dp->pixel_base);
> > +
> > +	if (IS_ERR(dp->panel)) {
> > +		DRM_ERROR("failed to initialize panel\n");
> > +		return NULL;
> > +	}
> > +
> > +	memcpy(dp_panel->dpcd, dp->panel->dpcd, DP_RECEIVER_CAP_SIZE);
> > +	memcpy(&dp_panel->link_info, &dp->panel->link_info,
> > +	       sizeof(dp->panel->link_info));
>
> Both these lines show that link_info and dpcd belong to msm_dp_display
> rather than the panel. The panel should only be describing properties of
> the particular sink.
I agree with your point.

This would require a larger cleanup of the panel abstraction, which
seems out of scope for this series. Could we address it in a separate 
refactoring series?

> > +
> > +	return dp_panel;
> > +}
> > +
> >   static void msm_dp_display_deinit_sub_modules(struct msm_dp_display_private *dp)
> >   {
> >   	msm_dp_audio_put(dp->audio);
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
> > index b1ea027438d952c94f3ae80725c92e46c631bdb2..d5889b801d190b6f33b180ead898c1e4ebcbf8f3 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.h
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.h
> > @@ -65,4 +65,6 @@ void msm_dp_display_unprepare(struct msm_dp *dp);
> >   
> >   int msm_dp_display_get_active_stream_cnt(struct msm_dp *msm_dp_display);
> >   
> > +struct msm_dp_panel *msm_dp_display_get_panel(struct msm_dp *msm_dp_display);
> > +
> >   #endif /* _DP_DISPLAY_H_ */
> >
> > --
> > 2.34.1