[Spice-devel] [PATCH linux vdagent] Don't abort if XRRSetCrtcConfig fails

[Christophe Fergeau]

On Mon, Dec 23, 2013 at 03:39:21PM +0200, Alon Levy wrote:
> On 12/19/2013 09:32 PM, Jonathon Jongsma wrote:
> > No, the cause is not identified yet.  Still debugging that.  This patch just makes the vdagent more robust in the meantime.  
> > 
> 
> using nomodeset fixes the problem for me (F19 guest from iso, upstream
> with the qemu patch below to reproduce the problem without nomodeset),
> so this is a kernel/X driver issue, still investigating.

Looking more into this, using nomodeset triggers this workaround:
http://cgit.freedesktop.org/xorg/driver/xf86-video-qxl/tree/src/qxl_driver.c#n819
    /* fake transform support, to allow agent to switch crtc mode */
    /* without X doing checks, see rrcrtc.c "Check screen size */
    /* bounds" */
    xf86RandR12SetTransformSupport (pScreen, TRUE);

which nicely points at the bit of code in the X server which causes the X
error in the RHEL6/kms guest situation:
http://cgit.freedesktop.org/xorg/xserver/tree/randr/rrcrtc.c#n1148

Christophe
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