On Tue, Jul 3, 2018 at 2:58 PM Rob Clark robdclark@gmail.com wrote:
On Tue, Jul 3, 2018 at 12:56 PM, Sean Paul seanpaul@chromium.org 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@gmail.com Signed-off-by: Sean Paul seanpaul@chromium.org
Tested-by: Rob Clark robdclark@gmail.com
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