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 --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index c681dc1..b9da890 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -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; }