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author | Paulo Zanoni <paulo.r.zanoni@intel.com> | 2013-12-07 02:29:01 +0400 |
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committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-12-07 02:37:12 +0400 |
commit | 798183c54799fbe1e5a5bfabb3a8c0505ffd2149 (patch) | |
tree | 546230472bb3226a0552fb58455983a14036460f /drivers/char | |
parent | ce58c32b106efbe228b33b65f1ef6ab505fb7840 (diff) | |
download | linux-798183c54799fbe1e5a5bfabb3a8c0505ffd2149.tar.xz |
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>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/char')
0 files changed, 0 insertions, 0 deletions