Hints for debugging a weird sw-cursor issue ?

Dave Airlie airlied at gmail.com
Wed Aug 31 20:36:32 UTC 2016

On 31 August 2016 at 22:10, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi All,
> I've noticed a weird sw-cursor issue when a slave-output is active
> (I believe this is a sw-cursor issue because show_cursor never
>  gets called when a slave-output is active at server start).
> I'm seeing this with both 1.18 and master and with both the
> intel and the modesetting drivers (running gnome3 / gnome-shell).
> Everything is fine until I start glxgears (*) then the cursor becomes
> invisible (flickering on the intel driver) when it is near the
> top of the screen. Basically there is a horizontal bar where
> the cursor does not show. Note this goes for the entire monitor,
> not just where glxgears is running. This bar is near the top of
> the screen, but not completely at the top, there is a small area
> near the top where the cursor still shows.
> Interestingly enough if I disable vblank for glxgears the problem
> remains, but the bar becomes smaller (less high).
> So anyone got any clues for debugging this ?

Sounds like some wierdass tearing,

since swcursor has to paint the cursor on the screen, so you might
be seeing frames where the cursor hasn't been painted yet.


More information about the xorg-devel mailing list