From: Frank Li <Frank.li@oss.nxp.com>
To: Michal Pecio <michal.pecio@gmail.com>
Cc: frank.li@nxp.com, corbet@lwn.net, dmaengine@vger.kernel.org,
hch@infradead.org, imx@lists.linux.dev,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, lizhijian@fujitsu.com, mst@redhat.com,
rdunlap@infradead.org
Subject: Re: [PATCH v2 1/1] docs: dma: correct dma_set_mask() sample code
Date: Mon, 17 Aug 2026 13:43:02 -0500 [thread overview]
Message-ID: <aoNWNkAhUZi6_pgH@SMW015318> (raw)
In-Reply-To: <20260817191731.104171a3.michal.pecio@gmail.com>
On Mon, Aug 17, 2026 at 07:17:31PM +0200, Michal Pecio wrote:
> [You don't often get email from michal.pecio@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> On Mon, 17 Aug 2026 10:50:35 -0500, Frank Li wrote:
> > On Sun, Aug 16, 2026 at 07:10:44AM +0200, Michal Pecio wrote:
> > > No realistic chance of the dev->dma_mask check (below) giving -EIO?
> >
> > dma_mask is pointer, which already initilized by bus driver before
> > call to probe.
> >
> > For example
> >
> > https://elixir.bootlin.com/linux/v7.1.8/source/drivers/base/platform.c#L634
> >
> > If you find one, which bus driver have not init it, please high light
> > it.
> >
> > > > dma_supported() will call dma_direct_supported or iommux's
> > > > dma_supported call back function.
> > >
> > > Aapparently, it may also use some 'dma_map_ops' and there is a bunch
> > > of those spread over drivers/ and arch/. But I gather they are
> > > expected to behave similarly as the functions named above?
> >
> > I grep it and checked at that time, all return 1 when >= 32. Now more
> > powerfull check tools avaible, you can double check it.
>
> Thank you. Sounds like it should work then, though I think that
> checking return status won't harm, just to cover unusual cases like
> regression in some obscure arch or people with buggy out of tree
> patches (which they "forget" to mention they are using).
Now, prefer don't check when >= 32 to keep code clean.
Frank
>
> Regards,
> Michal
prev parent reply other threads:[~2026-08-17 18:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-01 17:41 [PATCH v2 1/1] docs: dma: correct dma_set_mask() sample code Frank Li
2024-04-02 15:09 ` Christoph Hellwig
2024-04-02 15:11 ` Jonathan Corbet
2024-04-02 15:43 ` Niklas Cassel
2024-04-02 16:08 ` Jonathan Corbet
2026-08-16 5:10 ` Michal Pecio
2026-08-17 15:50 ` Frank Li
2026-08-17 17:17 ` Michal Pecio
2026-08-17 18:43 ` Frank Li [this message]
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=aoNWNkAhUZi6_pgH@SMW015318 \
--to=frank.li@oss.nxp.com \
--cc=corbet@lwn.net \
--cc=dmaengine@vger.kernel.org \
--cc=frank.li@nxp.com \
--cc=hch@infradead.org \
--cc=imx@lists.linux.dev \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lizhijian@fujitsu.com \
--cc=michal.pecio@gmail.com \
--cc=mst@redhat.com \
--cc=rdunlap@infradead.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.