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 <[email protected]> Signed-off-by: Ville Syrjälä <[email protected]> Reviewed-by: Jesse Barnes <[email protected]> Reviewed-by: Chris Wilson <[email protected]> Signed-off-by: Daniel Vetter <[email protected]>
SKAPUSTIANSKYI · Mar 23, 2015 · 9848de0 · 9848de0
1 parent 0b37a9a
commit 9848de0
Showing 1 changed file with 2 additions and 2 deletions.
diff --git 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();					\
 		}							\