On Mon, 01 Jun 2020 14:48:58 +0000 Simon Ser contact@emersion.fr wrote:
Describe what a "BAD" link-status means for user-space and how it should handle it. The logic described has been implemented in igt [1].
Signed-off-by: Simon Ser contact@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Manasi Navare manasi.d.navare@intel.com Cc: Pekka Paalanen ppaalanen@gmail.com
drivers/gpu/drm/drm_connector.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index f2b20fd66319..08ba84f9787a 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -994,6 +994,12 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
after modeset, the kernel driver may set this to "BAD" and issue ahotplug uevent. Drivers should update this value usingdrm_connector_set_link_status_property().
When user-space receives the hotplug uevent and detects a "BAD"
link-status, the connector is no longer enabled. The list of available
modes may have changed. User-space is expected to pick a new mode if
the current one has disappeared and perform a new modeset with
link-status set to "GOOD" to re-enable the connector.- non_desktop:
- Indicates the output should be ignored for purposes of displaying a
- standard desktop environment or console. This is most likely because
Hi,
makes sense to me. Can it happen that there will be no modes left in the list?
What if userspace is driving two connectors from the same CRTC, and only one connector gets link-status bad, what does it mean? Is the other connector still running as normal, as if the failed connector didn't even exist?
That is mostly a question about what happens if userspace does not fix up the link-status=bad connector and does not detach it from the CRTC, but keeps on flipping or modesetting as if the failure never happened. I guess I could ask it about both a CRTC that has another connector still good, and a CRTC where the failed connector was the only one.
Can I trust that if the other connector is in any way affected, it too will get link-status bad?
Thanks, pq