[Intel-gfx] [RFC PATCH] drm/i915: replace platform flags with a platform enum

[Jani Nikula]

On Fri, 18 Nov 2016, Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com> wrote:
> On 18/11/2016 14:20, Jani Nikula wrote:
>> The platform flags in device info are (mostly) mutually
>> exclusive. Replace the flags with an enum. Add the platform enum also
>> for platforms that previously didn't have a flag, and give them codename
>> logging in dmesg.
>
> It just saddens me a bit that it prevents the compiler optimisation of 
> our IS_THIS || IS_THAT || IS_TAT ugliness. :I On the basis on that I 
> cannot quite make myself to support it, although it conceptually does 
> make more sense.

Personally I think making more sense conceptually trumps possible
compiler optimizations, especially when the code paths where this
actually matters are extremely rare. (Can you even point me at an
example where this makes a difference?)

That said, does doing something silly like this make a difference:

enum intel_platform {
	INTEL_PLATFORM_UNINITIALIZED = 0,
	INTEL_I830		= BIT(0),
	INTEL_I845G		= BIT(1),
	INTEL_I85X		= BIT(2),
	INTEL_I865G		= BIT(3),
	INTEL_I915G		= BIT(4),
	INTEL_I915GM		= BIT(5),
	INTEL_I945G		= BIT(6),
	INTEL_I945GM		= BIT(7),
	INTEL_G33		= BIT(8),
	INTEL_G4X		= BIT(9),
	INTEL_PINEVIEW		= BIT(10),
	INTEL_BROADWATER	= BIT(11),
	INTEL_CRESTLINE		= BIT(12),
	INTEL_IRONLAKE		= BIT(13),
	INTEL_SANDYBRIDGE	= BIT(14),
	INTEL_IVYBRIDGE		= BIT(15),
	INTEL_VALLEYVIEW	= BIT(16),
	INTEL_CHERRYVIEW	= BIT(17),
	INTEL_HASWELL		= BIT(18),
	INTEL_BROADWELL		= BIT(19),
	INTEL_SKYLAKE		= BIT(20),
	INTEL_BROXTON		= BIT(21),
	INTEL_KABYLAKE		= BIT(22),
};

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center