From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
intel-gfx@lists.freedesktop.org,
dri-devel <dri-devel@lists.freedesktop.org>,
Sebastian Siewior <bigeasy@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Chris Wilson <chris@chris-wilson.co.uk>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD
Date: Fri, 1 May 2020 15:55:14 -0600 [thread overview]
Message-ID: <CAHmME9pDtoPOwMGZuFAyYyWpOs8cnVO8t3FeOTR+YTeKL6PETg@mail.gmail.com> (raw)
In-Reply-To: <20200501180731.GA2485@infradead.org>
On Fri, May 1, 2020 at 12:07 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Thu, Apr 30, 2020 at 04:10:16PM -0600, Jason A. Donenfeld wrote:
> > Sometimes it's not okay to use SIMD registers, the conditions for which
> > have changed subtly from kernel release to kernel release. Usually the
> > pattern is to check for may_use_simd() and then fallback to using
> > something slower in the unlikely case SIMD registers aren't available.
> > So, this patch fixes up i915's accelerated memcpy routines to fallback
> > to boring memcpy if may_use_simd() is false.
>
> Err, why does i915 implements its own uncached memcpy instead of relying
> on core functionality to start with?
I was wondering the same. It sure does seem like this ought to be more
generalized functionality, with a name that represents the type of
transfer it's optimized for (wc or similar).
next prev parent reply other threads:[~2020-05-01 21:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 22:10 [PATCH] drm/i915: check to see if SIMD registers are available before using SIMD Jason A. Donenfeld
2020-05-01 10:42 ` Sebastian Andrzej Siewior
2020-05-01 11:34 ` David Laight
2020-05-01 21:54 ` Jason A. Donenfeld
2020-05-01 18:07 ` Christoph Hellwig
2020-05-01 21:55 ` Jason A. Donenfeld [this message]
2020-05-03 20:20 ` Chris Wilson
2020-05-04 16:03 ` Christoph Hellwig
2020-05-04 16:15 ` David Laight
2020-05-03 20:30 ` Chris Wilson
2020-05-03 20:35 ` Jason A. Donenfeld
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAHmME9pDtoPOwMGZuFAyYyWpOs8cnVO8t3FeOTR+YTeKL6PETg@mail.gmail.com \
--to=jason@zx2c4.com \
--cc=bigeasy@linutronix.de \
--cc=chris@chris-wilson.co.uk \
--cc=dri-devel@lists.freedesktop.org \
--cc=hch@infradead.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).