Re: [PATCH v4 01/39] drm/msm/dp: remove cached drm_edid from panel

[Yongxing Mou]

On 5/20/2026 5:22 PM, Dmitry Baryshkov wrote:
> On Tue, May 19, 2026 at 03:27:00PM +0800, Yongxing Mou wrote:
> > On 4/10/2026 9:52 PM, Dmitry Baryshkov wrote:
> > > On Fri, Apr 10, 2026 at 05:33:36PM +0800, Yongxing Mou wrote:
> > > > The cached drm_edid seems unnecessary here. Use the drm_edid pointer
> > > > directly in the plug stage instead of caching it. Remove the cached
> > > > drm_edid and the corresponding oneliner to simplify the code.
> > > >
> > > > Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/gpu/drm/msm/dp/dp_display.c | 27 +++++++++++-------
> > > >    drivers/gpu/drm/msm/dp/dp_panel.c   | 57 ++++---------------------------------
> > > >    drivers/gpu/drm/msm/dp/dp_panel.h   | 13 +++------
> > > >    3 files changed, 26 insertions(+), 71 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> > > > index 5c6a24ec140d..e28cc1bbb5b1 100644
> > > > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > > > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > > > @@ -268,6 +268,7 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
> > > >    	const struct drm_display_info *info = &connector->display_info;
> > > >    	int rc = 0;
> > > >    	u8 dpcd[DP_RECEIVER_CAP_SIZE];
> > > > +	const struct drm_edid *drm_edid;
> > > >    	rc = drm_dp_read_dpcd_caps(dp->aux, dpcd);
> > > >    	if (rc)
> > > > @@ -275,10 +276,20 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
> > > >    	dp->link->lttpr_count = msm_dp_display_lttpr_init(dp, dpcd);
> > > > -	rc = msm_dp_panel_read_sink_caps(dp->panel, connector);
> > > > +	rc = msm_dp_panel_read_link_caps(dp->panel, connector);
> > > >    	if (rc)
> > > >    		goto end;
> > > > +	drm_edid = drm_edid_read_ddc(connector, &dp->aux->ddc);
> > >
> > > Where is it free?
> > Ohh, i miss it, will update next version
> > > > +	drm_edid_connector_update(connector, drm_edid);
> > > > +
> > > > +	if (!drm_edid) {
> > > > +		DRM_ERROR("panel edid read failed\n");
> > > > +		/* check edid read fail is due to unplug */
> > > > +		if (!msm_dp_aux_is_link_connected(dp->aux))
> > >
> > > Does this work for USB-C AltMode usecase?
> > For USB-C DP, i think it always TRUE, here should already existed before
> > this patch..
>
> I'd expect the answer without the 'i think' part.
Sorry.Add log and tested.  For  USB-C AltMode usecase 
msm_dp_aux_is_link_connected() always return 0.
> > > > +			return -ETIMEDOUT;
> > > > +	}
> > > > +
> > > >    	msm_dp_link_process_request(dp->link);
> > > >    	if (!dp->msm_dp_display.is_edp)