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From: Doug Anderson <dianders@chromium.org>
To: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Maulik Shah <mkshah@codeaurora.org>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] soc: qcom: rpmh-rsc: Don't use ktime for timeout in write_tcs_reg_sync()
Date: Thu, 18 Jun 2020 14:52:32 -0700	[thread overview]
Message-ID: <CAD=FV=W9=cWZpW10ecG9_DmpWCEVhJ9C_AzbP4fTqdPQFZPhZw@mail.gmail.com> (raw)
In-Reply-To: <20200528074530.1.Ib86e5b406fe7d16575ae1bb276d650faa144b63c@changeid>

Bjorn and Andy,

On Thu, May 28, 2020 at 7:48 AM Douglas Anderson <dianders@chromium.org> wrote:
>
> The write_tcs_reg_sync() may be called after timekeeping is suspended
> so it's not OK to use ktime.  The readl_poll_timeout_atomic() macro
> implicitly uses ktime.  This was causing a warning at suspend time.
>
> Change to just loop 1000000 times with a delay of 1 us between loops.
> This may give a timeout of more than 1 second but never less and is
> safe even if timekeeping is suspended.
>
> NOTE: I don't have any actual evidence that we need to loop here.
> It's possibly that all we really need to do is just read the value
> back to ensure that the pipes are cleaned and the looping/comparing is
> totally not needed.  I never saw the loop being needed in my tests.
> However, the loop shouldn't hurt.
>
> Fixes: 91160150aba0 ("soc: qcom: rpmh-rsc: Timeout after 1 second in write_tcs_reg_sync()")
> Reported-by: Maulik Shah <mkshah@codeaurora.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
>  drivers/soc/qcom/rpmh-rsc.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)

Is it a good time to land this change now that -rc1 has come out?
It'd be nice to get this resolved.

Thanks!

-Doug

  parent reply	other threads:[~2020-06-18 21:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-28 14:48 [PATCH] soc: qcom: rpmh-rsc: Don't use ktime for timeout in write_tcs_reg_sync() Douglas Anderson
2020-05-28 22:44 ` Stephen Boyd
2020-05-29 17:00   ` Doug Anderson
2020-06-18 21:52 ` Doug Anderson [this message]
2020-06-24  4:41 ` Maulik Shah

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