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

[Dmitry Baryshkov]

On Wed, Apr 01, 2026 at 05:43:48PM +0800, Yongxing Mou wrote:
> 
> 
> 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?

I'd say, no. Or "yes, please send the cleanup first". I definitely don't
want to get more ugly code in the driver.

> 
> > > +
> > > +	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
> > > 
> > 
> 

-- 
With best wishes
Dmitry