drm/i915: Use usleep_range() in wait_for()
msleep() can sleep for way too long, so switch wait_for() to use
usleep_range() instead. Following a totally unscientific method
I just picked the range as W-2W.
This cuts the i915 init time on my BSW to almost half:
- initcall i915_init+0x0/0xa8 [i915] returned 0 after 419977 usecs
+ initcall i915_init+0x0/0xa8 [i915] returned 0 after 238419 usecs
Note that I didn't perform any other benchmarks on this so far.
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 6f20f3a..d2a4de0 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -56,8 +56,8 @@
ret__ = -ETIMEDOUT; \
break; \
} \
- if (W && drm_can_sleep()) { \
- msleep(W); \
+ if ((W) && drm_can_sleep()) { \
+ usleep_range((W)*1000, (W)*2000); \
} else { \
cpu_relax(); \
} \