[Intel-gfx] [PATCH] drm/i915: Drop platform_mask

[Ville Syrjälä]

On Fri, Mar 15, 2019 at 07:13:49AM +0000, Tvrtko Ursulin wrote:
> 
> On 15/03/2019 06:56, Tvrtko Ursulin wrote:
> > 
> > On 15/03/2019 00:52, Chris Wilson wrote:
> >> Quoting José Roberto de Souza (2019-03-15 00:42:35)
> >>> We don't have any platform that is composed by 2 or more platforms so
> >>> we don't need a mask, lets drop it and remove the actual limit of 32
> >>> platforms.
> > 
> > Platform mask was a nifty trick to compile tests like IS_SKYLAKE || 
> > IS_BROADWELL etc into a single conditional.
> > 
> >> gcc doesn't entirely agree, this is a net loss here (i.e. code size
> >> increases).
> > 
> > Perhaps the size re-gain of dropping the platform mask could be checked 
> > against the size gain of making the mask 64 bit.
> 
> One possible alternative could be splitting the 64-bit platform mask 
> into two 32-bit dwords. Like:
> 
>    u32 platform_mask[2];
> 
>    #define IS_PLATFORM(p) (platform_mask[p / 32] & BIT(p % 32))

This is fast approaching nih bitmap.h territory.

-- 
Ville Syrjälä
Intel