From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
Cc: Mayur Kumar <kmayur809@gmail.com>,
rafael@kernel.org, daniel.lezcano@kernel.org,
rui.zhang@intel.com, lukasz.luba@arm.com,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] thermal: armada: replace msleep with usleep_range for short durations
Date: Tue, 19 May 2026 09:43:45 +0200 [thread overview]
Message-ID: <87se7nsv2m.fsf@bootlin.com> (raw)
In-Reply-To: <9ae2a769-4b2a-4990-90d4-0a1c0f05ba82@oss.qualcomm.com> (Daniel Lezcano's message of "Mon, 18 May 2026 19:57:46 +0200")
Hello Mayur, Daniel,
Actually I have a couple of comments :-)
On 18/05/2026 at 19:57:46 +02, Daniel Lezcano <daniel.lezcano@oss.qualcomm.com> wrote:
> On 5/11/26 17:37, Mayur Kumar wrote:
>> The checkpatch tool warns that msleep(10) can sleep for up to 20ms.
This is a tool that gives you raw advices. Is sleeping 20ms a problem in
an init function, clearly outside of any hotpath? Honestly that does not
look like a big issue to me.
>> According to Documentation/timers/timers-howto.rst, usleep_range()
This file has been dropped in favour of a more up-to-date
Documentation/timers/delay_sleep_functions.rst in:
1f455f601e20 ("timers/Documentation: Cleanup delay/sleep documentation")
>> should be used for delays between 1ms and 20ms to provide better
>> timing accuracy.
Again, I don't see the point here, we do not need accuracy, do we?
>> Replace the 10ms msleep with a 10ms-11ms usleep_range.
10 to 11ms feels very arbitrary and has been selected just for getting
the tool happy. The above file states:
#. Use `fsleep()` whenever unsure (as it combines all the advantages of the
others)
#. Use `*sleep()` whenever possible
#. Use `usleep_range*()` whenever accuracy of `*sleep()` is not sufficient
#. Use `*delay()` for very, very short delays
Accuracy not being a concern here, fsleep() could be the way to go, and
the actual implementation would end up being usleep_range(10000, 20000),
which is exactly what the tool complains about.
In general I would be in favour of avoiding this kind of change that is
not motivated by hardware concerns, but if you really want to fix this
checkpatch.pl warning I believe in such case you should go for an
fsleep().
Thanks,
Miquèl
prev parent reply other threads:[~2026-05-19 7:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-11 15:37 [PATCH] thermal: armada: replace msleep with usleep_range for short durations Mayur Kumar
2026-05-18 17:57 ` Daniel Lezcano
2026-05-19 7:43 ` Miquel Raynal [this message]
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