Bug#616389: xserver-xorg-video-radeon: Crashes when closing graphical VT ("(EE) RADEON(0): failed to set mode: Permission denied")

[Michel Dänzer]

On Don, 2011-03-10 at 12:38 +0000, Thue Janus Kristensen wrote: 
> "finish" doesn't display the return value, because there is no debug
> symbols.

Install libdrm2-dbg? :)


> A random page on the Internet said that the return value is probably
> in eax. Doing 
> 
> 
> > print $eax
> 
> 
> after "finish" on drmDropMaster on the second X server, I get the
> value "-1".

Can you get the value of errno as well?

This does indicate that the DRM_IOCTL_DROP_MASTER may be failing, which
could explain the problem. The question why it would fail. Looking at
drm_dropmaster_ioctl() in the kernel, I think the only relevant case is

        if (!file_priv->minor->master)
                return -EINVAL;

but I don't know how file_priv->minor->master could be NULL. 

-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer