Unfortunately as a few of you are aware, Skylake is still very prone to pipe underruns. Most of this comes from not doing things atomically enough (e.g. needing to ensure that we update watermarks with other plane attributes, not forcefully flushing pipes until we need to, etc.). Now that I've finally got a grasp on how double buffered registers, arming registers, etc. works on skl, I've written up patches that fix most of the pipe underruns on Skylake.
When I say "most", I'm referring to the fact that I still seem to be able to reproduce pipe underruns, but this seems to be strictly exclusive to when pipes are being disabled. This means things *still* need to be made more atomic (sigh), but at least this is a start. Testing this series with a chamelium[1], mainly so I could heavily stress test the hotplugging of displays, I'm no longer able to reproduce pipe underruns when enabling another pipe. I've also tried reproducing underruns using xdotool to move the cursor in X from one monitor to another as quickly as possible (e.g. > 60 fps), and am no longer able to reproduce underruns there either with this patch series. Signed-off-by: Lyude Paul <cpaul at redhat.com> Cc: stable at vger.kernel.org Cc: Ville Syrjälä <ville.syrjala at linux.intel.com> Cc: Daniel Vetter <daniel.vetter at intel.com> Cc: Radhakrishna Sripada <radhakrishna.sripada at intel.com> Cc: Hans de Goede <hdegoede at redhat.com> <cpaul at redhat.com> Cc: Matt Roper <matthew.d.roper at intel.com> [1]: https://www.chromium.org/chromium-os/testing/chamelium Lyude (2): drm/i915/skl: Update plane watermarks atomically during plane updates drm/i915/skl: Don't mark pipes as dirty unless we've added/removed pipes drivers/gpu/drm/i915/intel_display.c | 47 ++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_pm.c | 31 +++++++++--------------- 2 files changed, 59 insertions(+), 19 deletions(-) -- 2.7.4
