From: Pratyush Yadav <pratyush@kernel.org>
To: "William A. Kennington III" <william@wkennington.com>
Cc: Tudor Ambarus <tudor.ambarus@linaro.org>,
Pratyush Yadav <pratyush@kernel.org>,
Michael Walle <mwalle@kernel.org>,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] mtd: spi-nor: Sleep between ready checks
Date: Tue, 27 May 2025 18:48:17 +0200 [thread overview]
Message-ID: <mafs0a56yrodq.fsf@kernel.org> (raw)
In-Reply-To: <20250523001412.878560-1-william@wkennington.com>
Hi William,
On Thu, May 22 2025, William A. Kennington III wrote:
> We have SPI NOR devices that respond very slowly (200ms+) to some
> commands. This causes our CPU to stall while repeatedly polling the NOR
> with no cooldown in between attempts. In order to reduce overhead, this
> patch introduces an exponential backoff in SPI readiness polling, that
> self tunes the polling interval to match the speed of most transactions.
>
> Signed-off-by: William A. Kennington III <william@wkennington.com>
I didn't read the code too deeply, but it seems full of magic values and
I am honestly not a big fan of how it reads. At the very least the logic
should be less black-magic. But since I didn't spend too much time
understanding the code, I don't have specific feedback for you.
BTW, you say it causes CPU stalls. The loop has a cond_resched() after
every iteration which I think gives the scheduler a chance to run other
tasks. Does that not work for some reason?
[...]
--
Regards,
Pratyush Yadav
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
prev parent reply other threads:[~2025-05-27 16:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-23 0:14 [PATCH RFC] mtd: spi-nor: Sleep between ready checks William A. Kennington III
2025-05-27 16:48 ` Pratyush Yadav [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=mafs0a56yrodq.fsf@kernel.org \
--to=pratyush@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=mwalle@kernel.org \
--cc=tudor.ambarus@linaro.org \
--cc=william@wkennington.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