X using radeon is refusing to start

[Chris Wilson]

On Fri, Feb 06, 2015 at 11:51:55AM +0900, Michel Dänzer wrote:
> On 06.02.2015 09:10, Andy Lutomirski wrote:
> > I just started getting X failures that say:
> > 
> > [   739.208] (EE) RADEON(0): [drm] failed to set drm interface version.
> > 
> > I'm not sure what triggered it.
> > 
> > dmesg says:
> > 
> > [  740.156499] [drm:drm_stub_open]
> > [  740.156502] [drm:drm_open_helper] pid = 2170, minor = 0
> > [  740.156541] [drm:drm_ioctl] pid=2170, dev=0xe200, auth=1,
> > DRM_IOCTL_MODE_GETRESOURCES
> > [  740.156557] [drm:drm_ioctl] pid=2170, dev=0xe200, auth=1,
> > DRM_IOCTL_MODE_GETRESOURCES
> > [  740.156575] [drm:drm_release] open_count = 2
> > [  740.156577] [drm:drm_release] pid = 2170, device = 0xe200, open_count = 2
> > [  740.158548] [drm:drm_ioctl] pid=2170, dev=0xe200, auth=1,
> > DRM_IOCTL_SET_VERSION
> > [  740.158549] [drm:drm_ioctl] ret = -13
> > [  740.159612] [drm:drm_framebuffer_reference] ffff8804457110a0: FB ID: 83 (3)
> > 
> > -13 means -EACCES.
> 
> We'd need to see dmesg from the beginning to be sure, but it looks like
> something (maybe plymouth or whatever boot splash you're using?) is
> keeping the DRM device open, so Xorg doesn't become DRM master.

The trick is to inspect /sys/kernel/debug/dri/%d/clients at the time it
fails and see who the kernel thinks is DRM_MASTER.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre