Re: [PATCH] drm/i915: Drop platform_mask

From: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
To: "Chris Wilson" <chris@chris-wilson.co.uk>,
	"José Roberto de Souza" <jose.souza@intel.com>,
	intel-gfx@lists.freedesktop.org
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Subject: Re: [PATCH] drm/i915: Drop platform_mask
Date: Fri, 15 Mar 2019 06:56:29 +0000	[thread overview]
Message-ID: <ea1e29d1-b185-896d-db35-c73eb8ab208a@linux.intel.com> (raw)
In-Reply-To: <155261112650.30576.7837349861887878724@skylake-alporthouse-com>

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.

However, one other benefit of the mask will also help with dead code 
elimination once per SKU build work is resurfaced. For the single 
selected platforms it doesn't matter, but for a subset it still does I 
think.

So I think we got two questions here - checking between size gains of 
the two options, and how interesting would multi-platform builds be.

One use case for the latter I had in mind was legacy vs execlists driver 
build but that wasn't based on any formal feature requests as far as I 
am aware.

Regards,

Tvrtko
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx