Re: 3.5 regression on i915

[Willy Tarreau]

Hi Chris,

On Sat, Oct 06, 2012 at 09:04:34AM +0100, Chris Wilson wrote:
> > The crash happens here in i915_gem_entervt_ioctl() :
> > 
> >     3659          BUG_ON(!list_empty(&dev_priv->mm.active_list));
> >     3660          BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
> >  -> 3661          BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
> >     3662          mutex_unlock(&dev->struct_mutex);
> 
> That BUG_ON there is silly and can simply be removed. The check is to
> verify that no batches were submitted to the kernel whilst the UMS/GEM
> client was suspended - to which the BUG_ONs are a crude approximation.
> Furthermore, the checks are too late, since it means we attempted to
> program the hardware whilst it was in an invalid state, the BUG_ONs are
> the least of your concerns at that point.

Excellent, that fixed it ! X still segfaults when KMS is used, but
I expect more of a pure user-space issue here since there is nothing
in dmesg.

Would some of you accept the following patch and tag it for -stable ?

Thanks,
Willy

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