Bug 79703 - Xinerama hiding the cursor in the wrong screen
Summary: Xinerama hiding the cursor in the wrong screen
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/fbdev (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
Depends on:
Reported: 2014-06-05 20:40 UTC by monnier
Modified: 2018-08-10 20:41 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

screen snapshot (360.83 KB, text/plain)
2014-06-05 20:40 UTC, monnier
no flags Details
Xorg.0.log (23.19 KB, text/plain)
2014-06-05 20:41 UTC, monnier
no flags Details

Description monnier 2014-06-05 20:40:36 UTC
Created attachment 100487 [details]
screen snapshot

Emacs by default hides the X11 mouse pointer/cursor while the user is typing text.
It recently changed the way it does so, by using the XFIXES extension.
This apparently bumps into a bug in the Xinerama driver:

- I start "emacs -Q" and place its window in the right screen.
- The mouse cursor is above the Emacs window.
- I type "a".
- Emacs asks the X server the hide the cursor, but it's "undrawn in the left
  screen instead" (i.e. a square blob is drawn at the corresponding place in the 
  left screen and the drawing of the cursor is still present in the right screen).
- I move the mouse a little: the previous cursor drawing is left along and a new
  mouse cursor is drawn at the new position.
- repeating this "type text + mouse mouse" I can end up with many ghost cursors
  on the right screen and correspondingly many "square blobs" on the left screen.

Of course, doing something such as switching workspace in my window-manager will redraw everything, which will get rid of those display artifacts.

This system is a Fit-PC2 (with the dreaded gma500 GPU) plus a displaylink USB->DVI adapter, running Debian testing.  The window manager is "ctwm".

See attached a copy of my Xorg.0.log as well as a screen snapshot.
Comment 1 monnier 2014-06-05 20:41:16 UTC
Created attachment 100488 [details]
Comment 2 GitLab Migration User 2018-08-10 20:41:43 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/xorg/driver/xf86-video-fbdev/issues/4.

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