From 828c79087cec61eaf4c76bb32c222fbe35ac3930 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Wed, 16 Oct 2013 09:21:30 -0700 Subject: drm/i915: Disable GGTT PTEs on GEN6+ suspend Once the machine gets to a certain point in the suspend process, we expect the GPU to be idle. If it is not, we might corrupt memory. Empirically (with an early version of this patch) we have seen this is not the case. We cannot currently explain why the latent GPU writes occur. In the technical sense, this patch is a workaround in that we have an issue we can't explain, and the patch indirectly solves the issue. However, it's really better than a workaround because we understand why it works, and it really should be a safe thing to do in all cases. The noticeable effect other than the debug messages would be an increase in the suspend time. I have not measure how expensive it actually is. I think it would be good to spend further time to root cause why we're seeing these latent writes, but it shouldn't preclude preventing the fallout. NOTE: It should be safe (and makes some sense IMO) to also keep the VALID bit unset on resume when we clear_range(). I've opted not to do this as properly clearing those bits at some later point would be extra work. v2: Fix bugzilla link Bugzilla: http://bugs.freedesktop.org/show_bug.cgi?id=65496 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=59321 Tested-by: Takashi Iwai Tested-by: Paulo Zanoni Signed-off-by: Ben Widawsky Tested-By: Todd Previte Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/i915_drv.c') diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 69d8ed5416c3..2ad27880cd04 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -505,6 +505,8 @@ static int i915_drm_freeze(struct drm_device *dev) intel_modeset_suspend_hw(dev); } + i915_gem_suspend_gtt_mappings(dev); + i915_save_state(dev); intel_opregion_fini(dev); @@ -648,7 +650,8 @@ static int i915_drm_thaw(struct drm_device *dev) mutex_lock(&dev->struct_mutex); i915_gem_restore_gtt_mappings(dev); mutex_unlock(&dev->struct_mutex); - } + } else if (drm_core_check_feature(dev, DRIVER_MODESET)) + i915_check_and_clear_faults(dev); __i915_drm_thaw(dev); -- cgit v1.2.3