[Intel-gfx] [PATCH 15/40] drm/i915: Priority boost for new clients

[Michal Wajdeczko]

On Tue, 25 Sep 2018 10:26:57 +0200, Chris Wilson  
<chris at chris-wilson.co.uk> wrote:

> Quoting Chris Wilson (2018-09-25 09:01:06)
>> Quoting Tvrtko Ursulin (2018-09-24 11:29:52)
>> >
>> > On 19/09/2018 20:55, Chris Wilson wrote:
>> > > diff --git a/drivers/gpu/drm/i915/i915_scheduler.h  
>> b/drivers/gpu/drm/i915/i915_scheduler.h
>> > > index 7edfad0abfd7..93e43e263d8c 100644
>> > > --- a/drivers/gpu/drm/i915/i915_scheduler.h
>> > > +++ b/drivers/gpu/drm/i915/i915_scheduler.h
>> > > @@ -19,12 +19,14 @@ enum {
>> > >       I915_PRIORITY_INVALID = INT_MIN
>> > >   };
>> > >
>> > > -#define I915_USER_PRIORITY_SHIFT 0
>> > > +#define I915_USER_PRIORITY_SHIFT 1
>> > >   #define I915_USER_PRIORITY(x) ((x) << I915_USER_PRIORITY_SHIFT)
>> > >
>> > >   #define I915_PRIORITY_COUNT BIT(I915_USER_PRIORITY_SHIFT)
>> > >   #define I915_PRIORITY_MASK (-I915_PRIORITY_COUNT)
>> > >
>> > > +#define I915_PRIORITY_NEWCLIENT      ((u8)BIT(0))
>> >
>> > Is the cast important and why?
>>
>> Unreliable memory says there was something iffy about the code  
>> generation
>> at one point.
>
> drivers/gpu/drm/i915/intel_lrc.c: In function  
> ‘__unwind_incomplete_requests’:
> drivers/gpu/drm/i915/intel_lrc.c:272:13: error: overflow in conversion  
> from ‘long unsigned int’ to ‘int’ changes value from  
> ‘18446744071562067969’ to ‘-2147483647’ [-Werror=overflow]
>   int prio = I915_PRIORITY_INVALID | I915_PRIORITY_NEWCLIENT;
>

If you plan to use I915_PRIORITY_NEWCLIENT in 'int' vars then
you should not use BIT macro that returns 'unsigned int long'

As I915_USER_PRIORITY is already using explicit shift, maybe the
same can be done for I915_PRIORITY_NEWCLIENT:

	#define I915_PRIORITY_NEWCLIENT      (1 << 0)

Michal