Strange cursor redraws

[Daniel Veillard]

  I have noticed that my cursor get redrawed generating cursor image flicker
even if I don't move the mouse or the underlying image doesn't change. It
didn't depend on the application having the focus, or over which the cursor
was drawn, but was depending on the cursor location on the screen. After a bit
of checking it appears to be related to virtual screen, if the cursor is
positionned at the x/y coordinate of a gnome-terminal whose content is
scrolling but not displayed due to being on another virtual screen, then
the cursor is redrawn as the terminal image is updated. Moving the cursor
coordinate outside of the terminal area stops the flicker.

   Using xorg-x11 6.8.1-12, gnome-terminal-2.7.3-1, and metacity-2.8.6-2.1,
hardware is Matrox 450 dual head running in xinerama mode.
Excerps from /var/log/Xorg.0.log:
  (--) PCI:*(1:0:0) Matrox Graphics, Inc. MGA G400 AGP rev 130,...
  (--) Chipset mgag400 found
  (**) MGA(0): Depth 16, (--) framebuffer bpp 16
  (==) MGA(0): RGB weight 565
  (II) MGA(0): Using XFree86 Acceleration Architecture (XAA)

  Does this qualify as a bug ? If yes what module is most likely to be guilty ?

Daniel

-- 
Daniel Veillard      | Red Hat Desktop team http://redhat.com/
veillard(a)redhat.com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/

[Owen Taylor]

On Mon, 2005-01-03 at 08:08 -0500, Daniel Veillard wrote:
>    I have noticed that my cursor get redrawed generating cursor image
> flicker
>  even if I don't move the mouse or the underlying image doesn't change. It
>  didn't depend on the application having the focus, or over which the cursor
>  was drawn, but was depending on the cursor location on the screen. After a bit
>  of checking it appears to be related to virtual screen, if the cursor is
>  positionned at the x/y coordinate of a gnome-terminal whose content is
>  scrolling but not displayed due to being on another virtual screen, then
>  the cursor is redrawn as the terminal image is updated. Moving the cursor
>  coordinate outside of the terminal area stops the flicker.
>  
>     Using xorg-x11 6.8.1-12, gnome-terminal-2.7.3-1, and metacity-2.8.6-2.1,
>  hardware is Matrox 450 dual head running in xinerama mode.
>  Excerps from /var/log/Xorg.0.log:
>    (--) PCI:*(1:0:0) Matrox Graphics, Inc. MGA G400 AGP rev 130,...
>    (--) Chipset mgag400 found
>    (**) MGA(0): Depth 16, (--) framebuffer bpp 16
>    (==) MGA(0): RGB weight 565
>    (II) MGA(0): Using XFree86 Acceleration Architecture (XAA)
>  
>    Does this qualify as a bug ? If yes what module is most likely to be guilty ? 
Well, if your description is accurate, that would be an X server bug. It
sort of sounds like something is not checking whether a window is
visible
before hiding the software cursor when drawing on that window.

(I don't think the MGA handles alpha cursors, so the bluecurve cursor
theme will give you a software cursor.)

Regards,
						Owen

[Daniel Veillard]

On Mon, Jan 03, 2005 at 02:00:32PM -0500, Owen Taylor wrote:
>  On Mon, 2005-01-03 at 08:08 -0500, Daniel Veillard wrote:
>  >   I have noticed that my cursor get redrawed generating cursor image flicker
>  > even if I don't move the mouse or the underlying image doesn't change. It
>  > didn't depend on the application having the focus, or over which the cursor
>  > was drawn, but was depending on the cursor location on the screen. After a bit
>  > of checking it appears to be related to virtual screen, if the cursor is
>  > positionned at the x/y coordinate of a gnome-terminal whose content is
>  > scrolling but not displayed due to being on another virtual screen, then
>  > the cursor is redrawn as the terminal image is updated. Moving the cursor
>  > coordinate outside of the terminal area stops the flicker.
>  > 
>  >    Using xorg-x11 6.8.1-12, gnome-terminal-2.7.3-1, and metacity-2.8.6-2.1,
>  > hardware is Matrox 450 dual head running in xinerama mode.
>  > Excerps from /var/log/Xorg.0.log:
>  >   (--) PCI:*(1:0:0) Matrox Graphics, Inc. MGA G400 AGP rev 130,...
>  >   (--) Chipset mgag400 found
>  >   (**) MGA(0): Depth 16, (--) framebuffer bpp 16
>  >   (==) MGA(0): RGB weight 565
>  >   (II) MGA(0): Using XFree86 Acceleration Architecture (XAA)
>  > 
>  >   Does this qualify as a bug ? If yes what module is most likely to be guilty ?
>  
>  Well, if your description is accurate, that would be an X server bug. It
>  sort of sounds like something is not checking whether a window is
>  visible
>  before hiding the software cursor when drawing on that window.
>  
>  (I don't think the MGA handles alpha cursors, so the bluecurve cursor
>  theme will give you a software cursor.) 
  okay, thanks !

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=144022

Daniel

-- 
Daniel Veillard      | Red Hat Desktop team http://redhat.com/
veillard(a)redhat.com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/