On Tue, Jul 3, 2018 at 2:58 PM Rob Clark <robdclark@xxxxxxxxx> wrote: > > On Tue, Jul 3, 2018 at 12:56 PM, Sean Paul <seanpaul@xxxxxxxxxxxx> wrote: > > The bridge loses its hw state when the cable is unplugged. If we detect > > this case in the hpd handler, reset its state. > > > > Reported-by: Rob Clark <robdclark@xxxxxxxxx> > > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> > > Tested-by: Rob Clark <robdclark@xxxxxxxxx> > > > --- > > This is the follow-up to "drm/msm: Disable mdp5 crtc when there are no > > active planes". I incorrectly assumed the modeset was required from the > > msm side, but Rob pointed out that he thought it might be a bridge > > issue. > > To elaborate, this is an atomic userspace (weston), when it sees the > display disconnected, it removes the planes from the CRTC but does not > disable the CRTC. So drm/msm sets up the LM to scanout a solid color, > and leaves the encoder and dsi cranking along happily. When > replugging the display, the atomic helpers see the CRTC is still > active and (correctly) doesn't do a full modeset. So the bridge is > not re-configured/re-enabled. > > Arguably this perhaps isn't what weston *wanted* to do, but in the end > the bug is in the bridge. > Fwiw, I've also filed https://gitlab.freedesktop.org/wayland/weston/issues/123 against weston so they can save some power on disconnected displays. But yeah, multiple pieces all working against each other here. Sean > We could possibly set the connector link_status to BAD as an > alternative. But at least the build of weston I'm using atm doesn't > handle the link_status propery, this approach requires each atomic > userspace to handle this case. Compared to Sean's approach which is > transparent to userspace, which seems attractive. > > BR, > -R > > > > > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > > index 73021b388e12..dd3ff2f2cdce 100644 > > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > > @@ -429,6 +429,18 @@ static void adv7511_hpd_work(struct work_struct *work) > > else > > status = connector_status_disconnected; > > > > + /* > > + * The bridge resets its registers on unplug. So when we get a plug > > + * event and we're already supposed to be powered, cycle the bridge to > > + * restore its state. > > + */ > > + if (status == connector_status_connected && > > + adv7511->connector.status == connector_status_disconnected && > > + adv7511->powered) { > > + regcache_mark_dirty(adv7511->regmap); > > + adv7511_power_on(adv7511); > > + } > > + > > if (adv7511->connector.status != status) { > > adv7511->connector.status = status; > > if (status == connector_status_disconnected) > > -- > > Sean Paul, Software Engineer, Google / Chromium OS > > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
