On Thu, Jan 15, 2026 at 09:39:29AM -0600, Bjorn Andersson wrote: > On Thu, Jan 15, 2026 at 10:30:49AM +0100, Konrad Dybcio wrote: > > On 1/15/26 8:29 AM, Dmitry Baryshkov wrote: > > > From: Jessica Zhang <[email protected]> > > > > > > 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. > > > > I think this part of the commit message no longer applies > > > > > > > > Signed-off-by: Jessica Zhang <[email protected]> > > > Signed-off-by: Dmitry Baryshkov <[email protected]> > > > --- > > > drivers/gpu/drm/msm/dp/dp_display.c | 11 ++++++----- > > > 1 file changed, 6 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..3184066adb15 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 +1690,12 @@ 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); > > > + drm_connector_set_link_status_property(dp->connector, > > > DRM_LINK_STATUS_BAD); > > > + } > > > > Previously failure in this call would have propagated an error > > > > msm_dp_ctrl_on_link() enables mainlink clocks, so > > > > Missed that one. I guess in practice it's not much difference from the > previous behavior - where the display just wouldn't work either, except > for the crash you point out below. > > It seems to be that it would make sense to return an error to userspace > when this happens, but the kernel-doc says: > > """ > The bridge can assume that the display pipe (i.e. clocks and timing > signals) feeding it is running when this callback is called. > """ > > What's the expected error path here?
None. The only thing we can do in atomic paths is to set the bad link_status and be ready not to crash (especially at the disable() path). > > Regards, > Bjorn > > > > + > > > msm_dp_display_enable(msm_dp_display, force_link_train); > > > > IIUC this will crash the machine if the above fails > > > > Konrad > > -- With best wishes Dmitry
