drm/i915: Disable semaphores by default on SNB

Semaphores still cause problems on some machines:

> From Udo Steinberg:
>
> With Linux-3.2-rc6 I'm frequently seeing GPU hangs when large amounts of
> text scroll in an xterm, such as when extracting a tar archive. Such as this
> one (note the timestamps):
>
>  I can reproduce it fairly easily with something
>  as simple as:
>
>	  while true; do dmesg; done

This patch turns them off on SNB while leaving them on for IVB.

Reported-by: Udo Steinberg <udo@hypervisor.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eugeni Dodonov <eugeni@dodonov.net>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Keith Packard 2011-12-26 17:02:10 -08:00 committed by Linus Torvalds
parent 7f54492fbc
commit ebbd857e6b

View File

@ -756,9 +756,9 @@ intel_enable_semaphores(struct drm_device *dev)
if (i915_semaphores >= 0)
return i915_semaphores;
/* Enable semaphores on SNB when IO remapping is off */
/* Disable semaphores on SNB */
if (INTEL_INFO(dev)->gen == 6)
return !intel_iommu_enabled;
return 0;
return 1;
}