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| author | Paulo Zanoni <paulo.r.zanoni@intel.com> | 2013-12-06 20:29:01 -0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-12-13 18:47:39 +0100 |
| commit | 96b4026878d9dac71bd4c3d6e05c7fbb16a3e0aa (patch) | |
| tree | 99bbc7fa03cbcafa398265a9f4391e110a48bddf | |
| parent | 4db080f9e93411c3c41ec402244da28e2bbde835 (diff) | |
| download | linux-96b4026878d9dac71bd4c3d6e05c7fbb16a3e0aa.tar.bz2 | |
drm/i915: change CRTC assertion on LCPLL disable
Currently, PC8 is enabled at modeset_global_resources, which is called
after intel_modeset_update_state. Due to this, there's a small race
condition on the case where we start enabling PC8, then do a modeset
while PC8 is still being enabled. The racing condition triggers a WARN
because intel_modeset_update_state will mark the CRTC as enabled, then
the thread that's still enabling PC8 might look at the data structure
and think that PC8 is being enabled while a pipe is enabled. Despite
the WARN, this is not really a bug since we'll wait for the
PC8-enabling thread to finish when we call modeset_global_resources.
The spec says the CRTC cannot be enabled when we disable LCPLL, so we
had a check for crtc->base.enabled. If we change to crtc->active we
will still prevent disabling LCPLL while the CRTC is enabled, and we
will also prevent the WARN above.
This is a replacement for the previous patch named
"drm/i915: get/put PC8 when we get/put a CRTC"
Testcase: igt/pm_pc8/modeset-lpsp-stress-no-wait
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
(cherry picked from commit 798183c54799fbe1e5a5bfabb3a8c0505ffd2149
from -next due to Dave's report.)
Reported-by: Dave Jones <davej@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 8b8bde7dce53..4049a65a9f8c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -6303,7 +6303,7 @@ static void assert_can_disable_lcpll(struct drm_i915_private *dev_priv) uint32_t val; list_for_each_entry(crtc, &dev->mode_config.crtc_list, base.head) - WARN(crtc->base.enabled, "CRTC for pipe %c enabled\n", + WARN(crtc->active, "CRTC for pipe %c enabled\n", pipe_name(crtc->pipe)); WARN(I915_READ(HSW_PWR_WELL_DRIVER), "Power well on\n"); |