drm/i915: Don't enable IPS when pixel rate exceeds 95%
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Wed, 3 Jun 2015 12:45:11 +0000 (15:45 +0300)
committerJani Nikula <jani.nikula@intel.com>
Fri, 12 Jun 2015 10:14:33 +0000 (13:14 +0300)
commit8cfb340774744438dea08a32072bea4a162dd132
treeebd322976b2c8c9cdbda5b0b49c5575e41c15f3f
parent44913155f036ae966f09a7bc0d299c31876b4383
drm/i915: Don't enable IPS when pixel rate exceeds 95%

Bspec says we shouldn't enable IPS on BDW when the pipe pixel rate
exceeds 95% of the core display clock. Apparently this can cause
underruns.

There's no similar restriction listed for HSW, so leave that one alone
for now.

v2: Add pipe_config_supports_ips() (Chris)
v3: Compare against the max cdclk insted of the current cdclk
v4: Rebased to the latest
v5: Rebased to the latest
v6: Fix for patch style problems

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83497
Tested-by: Timo Aaltonen <tjaalton@ubuntu.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drivers/gpu/drm/i915/intel_display.c
drivers/gpu/drm/i915/intel_drv.h
drivers/gpu/drm/i915/intel_pm.c