From: Mark Brown <broonie@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Robin Murphy <robin.murphy@arm.com>,
Phil Elwell <phil@raspberrypi.com>,
linux-spi <linux-spi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] spi: Skip zero-length transfers in spi_transfer_one_message()
Date: Fri, 12 Feb 2021 13:05:30 +0000 [thread overview]
Message-ID: <20210212130530.GE6057@sirena.org.uk> (raw)
In-Reply-To: <CAMuHMdXFt-0vyBQnvwWim8MrijZ-PNN0HsO+dDp9iMzb2153Hg@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 870 bytes --]
On Fri, Feb 12, 2021 at 01:57:24PM +0100, Geert Uytterhoeven wrote:
> On Fri, Feb 12, 2021 at 1:55 PM Mark Brown <broonie@kernel.org> wrote:
> > No, I think it's fine - there's probably some sensible use case with
> > drivers reusing a statically allocated transfer/buffer set for multiple
> > operations and just tweaking the length as needed which seems a bit
> > weird but I can't think of a reason not to allow it. Your patch is
> > currently queued, all being well it'll get tested & pushed out later
> > today.
> Aren't the zero-length transfers also used to do tricks with the CS signal,
> e.g. combined with cs_change?
The issue wasn't that things were using zero length transfers, the issue
was that drivers were doing zero length transfers but also passing data
buffers which isn't an obvious thing to do given that there will be no
data in those buffers.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2021-02-12 13:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 18:08 [PATCH] spi: Skip zero-length transfers in spi_transfer_one_message() Nicolas Saenz Julienne
2021-02-12 12:31 ` Mark Brown
2021-02-12 12:48 ` Nicolas Saenz Julienne
2021-02-12 12:52 ` Mark Brown
2021-02-12 12:57 ` Geert Uytterhoeven
2021-02-12 13:05 ` Mark Brown [this message]
2021-02-12 14:01 ` Mark Brown
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=20210212130530.GE6057@sirena.org.uk \
--to=broonie@kernel.org \
--cc=geert@linux-m68k.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
--cc=nsaenzjulienne@suse.de \
--cc=phil@raspberrypi.com \
--cc=robin.murphy@arm.com \
/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