Re: [PATCH v5 04/10] drm/msm/dp: Move link training to atomic_enable()

[Dmitry Baryshkov]

On Fri, May 22, 2026 at 01:33:07PM +0200, Konrad Dybcio wrote:
> On 3/14/26 2:09 AM, Dmitry Baryshkov wrote:
> > From: Jessica Zhang <jesszhan0024@xxxxxxxxx>
> > 
> > Currently, the DP link training is being done during HPD. Move
> > link training to atomic_enable() in accordance with the atomic_enable()
> > documentation.
> > 
> > Link disabling is already done in atomic_post_disable() (as part of the
> > dp_ctrl_off_link_stream() helper).
> > 
> > Finally, call the plug/unplug handlers directly in hpd_notify() instead
> > of queueing them in the event thread so that they aren't preempted by
> > other events.
> > 
> > Signed-off-by: Jessica Zhang <jessica.zhang@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/msm/dp/dp_display.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> > index a05144de3b93..e7b1ed5491c4 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > @@ -436,11 +436,6 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
> >  	msm_dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> >  
> >  	msm_dp_link_reset_phy_params_vx_px(dp->link);
> > -	rc = msm_dp_ctrl_on_link(dp->ctrl);
> > -	if (rc) {
> > -		DRM_ERROR("failed to complete DP link training\n");
> > -		goto end;
> > -	}
> >  
> >  	msm_dp_add_event(dp, EV_USER_NOTIFICATION, true, 0);
> >  
> > @@ -1695,6 +1690,11 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
> >  		force_link_train = true;
> >  	}
> >  
> > +	rc = msm_dp_ctrl_on_link(msm_dp_display->ctrl);
> > +	if (rc)
> > +		DRM_ERROR("Failed link training (rc=%d)\n", rc);
> 
> So this will still crash the device if the above fails - there's some
> return statements in this function, should we bail out if that happens?

Yes.

> 
> Konrad

-- 
With best wishes
Dmitry