Problem with Intel emgd (GMA500)

Éric Piel E.A.B.Piel at
Mon Oct 17 17:00:07 PDT 2011

Op 10-10-11 14:52, Alan Cox schreef:
>> xrandr: Failed to get size of gamma for output default
>> xrandr: screen cannot be larger that 640x480 (desired size 800x600)
>> xrandr: Configure crtc 0 failed
> xrandr won't allow you to change modes on the fbdev interface. The libdrm
> tools will if it detected any other modes, however it tries to default to
> the reported LCD panel size so you ought to get the size of your panel as
> the default behaviour.

For a long time, plugging a HDMI screen with my laptop would crash it. 
However, I've just tried again and to my surprise, with 3.1-rc9, it goes 
as far as displaying the picture. Great work!

Nevertheless, the selected mode is 1024x768, which is smaller than the 
native modes of both the LCD panel and the external screen (it could be 
the highest common resolution, though). So this lead me to two questions:
* Could you explain more how to change the modes of the fbdev? I've 
tried the tools with libdrm (modetest, modeprint, kmstest...) and they 
all fail to find a compatible device. What argument do you pass them? 
Also, fbset displays correct information but when trying to change the 
mode it seems to always fail with this:
ioctl FBIOPUT_VSCREENINFO: Invalid argument

* Is there a way to have the two screens display different image (i.e. 
not clone mode)? Or maybe just force to use only the external screen 
with its native resolution?


More information about the xorg mailing list