drm/i915/gen9: Re-allocate DDB only for changed pipes
authorMatt Roper <matthew.d.roper@intel.com>
Mon, 27 Jun 2016 23:42:44 +0000 (16:42 -0700)
committerMatt Roper <matthew.d.roper@intel.com>
Tue, 28 Jun 2016 17:48:11 +0000 (10:48 -0700)
commit9b6130227495fdaf17f8b3b28db083666b113c84
tree10e79a55c098559cdc5b7e1ed9c42bccd6654754
parentbdaa2dfbba3e07e171bccd2404fa3f75dbc66972
drm/i915/gen9: Re-allocate DDB only for changed pipes

When a display update triggers a DDB re-allocation, we should start by
assuming that only the updated pipes need to be re-allocated (we have
logic later that may add additional pipes if, e.g., a modeset triggers a
change to the global allocation).

We were erroneously using the _active_ pipes as our starting point
rather than the changed pipes.  This causes us to grab CRTC locks that
we didn't actually need, reducing parallelism.  Given the recent
non-blocking atomic changes, it also causes legacy pageflips against one
CRTC to return -EBUSY if there's an outstanding pageflip against a
different CRTC (a situation easily triggered via compositors like
Weston).

Fixes: 98d39494d3 ("drm/i915/gen9: Compute DDB allocation at atomic check time (v4)")
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467070964-14864-1-git-send-email-matthew.d.roper@intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
drivers/gpu/drm/i915/intel_pm.c