sna: Wrap rrGetInfo so that we can probe when udev is not active

If the ddx is configured without udev support, we do not receive
notifications when the MST topology is changed. This leads us to query
the kernel for bad connectors, and so we end up reporting an unknown
connection status for them, which the user and client often find
confusing. However, we can not simply act upon the detection failure as
we are too deep inside the callback chain and cannot change the arrays of
known connectors whilst iterating over them. A neat compromise is to
hook into the rrGetInfo call chain and poll for MST changes before we
report back the current configuration.

References: https://bugs.freedesktop.org/show_bug.cgi?id=84718
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/sna/sna.h b/src/sna/sna.h
index e0356343..4cd85d19 100644
--- a/src/sna/sna.h
+++ b/src/sna/sna.h
@@ -312,6 +312,8 @@ struct sna {
 		struct udev_monitor *backlight_monitor;
 		pointer backlight_handler;
 #endif
+
+		Bool (*rrGetInfo)(ScreenPtr, Rotation *);
 	} mode;
 
 	struct {