linux-kernel - Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD

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Message-ID: <20200504160314.GA26373@infradead.org>
Date:   Mon, 4 May 2020 09:03:14 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Chris Wilson <chris@...is-wilson.co.uk>
Cc:     "Jason A. Donenfeld" <Jason@...c4.com>,
        Christoph Hellwig <hch@...radead.org>,
        linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, bigeasy@...utronix.de,
        tglx@...utronix.de, stable@...r.kernel.org
Subject: Re: [PATCH] drm/i915: check to see if SIMD registers are available
 before using SIMD

On Sun, May 03, 2020 at 09:20:19PM +0100, Chris Wilson wrote:
> > Err, why does i915 implements its own uncached memcpy instead of relying
> > on core functionality to start with?
> 
> What is this core functionality that provides movntqda?

A sensible name might be memcpy_uncached or mempcy_nontemporal.
But the important point is that this should be arch code with a common
fallback rather than hacking it up in drivers.