drm/i915: Use usleep_range() in wait_for()
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Fri, 20 Mar 2015 19:28:08 +0000 (21:28 +0200)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Mon, 23 Mar 2015 09:30:16 +0000 (10:30 +0100)
commit9848de082ff400f8b88e6d550bfce551838af69c
tree63289e17f9c1adfe8fa2067b6605e28f38a7a264
parent0b37a9a9ebdf47dc9d5290a1c69bd944dde5cc15
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>
drivers/gpu/drm/i915/intel_drv.h