Any ideas about this? (i915 caused kernel oops while suspending to RAM)

Chris Wilson chris at
Tue Mar 22 14:34:11 PDT 2011

On Tue, 22 Mar 2011 22:21:24 +0100, Łukasz Maśko <ed at> wrote:
> It says (or at leas it seems so) that it was the i915 graphics drm module 
> which caused it. My machine has i945GM graphics chipset. Currently I'm 
> running xserver 1.10.0 and intel driver 2.14.0. Both of these oopses 
> happened with kernel, which I've been using since Saturday. There 
> were no such problems with earlier kernels.

You were fortunate, as the bug in all its guises is much older indeed.
The final fix, I hope, was:

commit 9334ef755f060e251f3f395caeda1a58b6834ea3
Author: Chris Wilson <chris at>
Date:   Fri Jan 28 11:53:03 2011 +0000

    drm: Don't switch fb when disabling an output
    In drm_crtc_helper_set_config, we call drm_crtc_helper_set_mode which
    may return early and do no operation if the crtc is to be disabled. In
    this case we merrily swap to the new fb, discarding the old_fb believing
    that it has been cleaned up. However, due to the early return, the
    old_fb was not presented to the backend for correct reaping, and nor was
    the new one - which is about to be reaped via the
    drm_helper_disable_unused_functions(), leading to incorrect refcounting
    of the pinned objects.
    Tested-by: Takashi Iwai <tiwai at>
    Signed-off-by: Chris Wilson <chris at>

Chris Wilson, Intel Open Source Technology Centre

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