Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > On Thu, Dec 15, 2016 at 10:47:57AM +0200, Jani Nikula wrote: >> On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: >> > usleep_range() is intended for delays in the 10us to 10ms range that need >> > good precision. a

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > On Thu, Dec 15, 2016 at 10:47:57AM +0200, Jani Nikula wrote: >> On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: >> > usleep_range() is intended for delays in the 10us to 10ms range that need >> > good precision. a useleep_range(1, will effectively be

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Nicholas Mc Guire
On Thu, Dec 15, 2016 at 10:47:57AM +0200, Jani Nikula wrote: > On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > > usleep_range() is intended for delays in the 10us to 10ms range that need > > good precision. a useleep_range(1, will effectively be no more than an > > imprecise

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Nicholas Mc Guire
On Thu, Dec 15, 2016 at 10:47:57AM +0200, Jani Nikula wrote: > On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > > usleep_range() is intended for delays in the 10us to 10ms range that need > > good precision. a useleep_range(1, will effectively be no more than an > > imprecise udelay with some

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Jani Nikula wrote: > On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: >> usleep_range() is intended for delays in the 10us to 10ms range that need >> good precision. a useleep_range(1, will effectively be no more than an >>

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Jani Nikula wrote: > On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: >> usleep_range() is intended for delays in the 10us to 10ms range that need >> good precision. a useleep_range(1, will effectively be no more than an >> imprecise udelay with some added cache disruption as

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > usleep_range() is intended for delays in the 10us to 10ms range that need > good precision. a useleep_range(1, will effectively be no more than an > imprecise udelay with some added cache disruption as it will fire more or > less

Re: [PATCH] drm/i915: use udelay for very small delays

2016-12-15 Thread Jani Nikula
On Thu, 15 Dec 2016, Nicholas Mc Guire wrote: > usleep_range() is intended for delays in the 10us to 10ms range that need > good precision. a useleep_range(1, will effectively be no more than an > imprecise udelay with some added cache disruption as it will fire more or > less immediately - use

[PATCH] drm/i915: use udelay for very small delays

2016-12-14 Thread Nicholas Mc Guire
usleep_range() is intended for delays in the 10us to 10ms range that need good precision. a useleep_range(1, will effectively be no more than an imprecise udelay with some added cache disruption as it will fire more or less immediately - use udelay() here. Fixes: commit be4fc046bed3 ("drm/i915:

[PATCH] drm/i915: use udelay for very small delays

2016-12-14 Thread Nicholas Mc Guire
usleep_range() is intended for delays in the 10us to 10ms range that need good precision. a useleep_range(1, will effectively be no more than an imprecise udelay with some added cache disruption as it will fire more or less immediately - use udelay() here. Fixes: commit be4fc046bed3 ("drm/i915: