drm/i915: Use I915_READ_FW for plane updates

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Optimize the plane register accesses a little bit by grabbing
the uncore lock manually across the entire pile of accesses and
using I915_READ_FW().

This helps keep the pipe update vblank evade critical section
below our 100 usec deadline, particularly with lockdep enabled.
And in general we want to keep that critical section as short
as possible as it's executed with interrupts disabled.

Not all plane updates currently happen from within the vblank evade
critical section, so we must use the irqsave/irqrestore variants
of the spinlock functions in the plane hooks.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170309154434.29303-5-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

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This commit is contained in:

Ville Syrjälä 2017-03-09 17:44:33 +02:00

parent 78587de299

commit dd584fc071

2 changed files with 228 additions and 158 deletions

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158

drivers/gpu/drm/i915/intel_display.c

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220

drivers/gpu/drm/i915/intel_sprite.c

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