From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Linux MMC List <linux-mmc@vger.kernel.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Ulrich Hecht <uli+renesas@fpond.eu>,
Simon Horman <horms+renesas@verge.net.au>,
Niklas Soderlund <niklas.soderlund@ragnatech.se>
Subject: Re: [PATCH 1/2] mmc: tmio: Further fixup runtime PM management at remove
Date: Wed, 20 May 2020 16:30:33 +0200 [thread overview]
Message-ID: <CAMuHMdXUuXLh1FWAoTTNraQQ7RGGmEOBFmaYdH71ccRovNEpgw@mail.gmail.com> (raw)
In-Reply-To: <20200519152434.6867-1-ulf.hansson@linaro.org>
Hi Ulf,
On Tue, May 19, 2020 at 5:24 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> Before calling tmio_mmc_host_probe(), the caller is required to enable
> clocks for its device, as to make it accessible when reading/writing
> registers during probe.
>
> Therefore, the responsibility to disable these clocks, in the error path of
> ->probe() and during ->remove(), is better managed outside
> tmio_mmc_host_remove(). As a matter of fact, callers of
> tmio_mmc_host_remove() already expects this to be the behaviour.
>
> However, there's a problem with tmio_mmc_host_remove() when the Kconfig
> option, CONFIG_PM, is set. More precisely, tmio_mmc_host_remove() may then
> disable the clock via runtime PM, which leads to clock enable/disable
> imbalance problems, when the caller of tmio_mmc_host_remove() also tries to
> disable the same clocks.
>
> To solve the problem, let's make sure tmio_mmc_host_remove() leaves the
> device with clocks enabled, but also make sure to disable the IRQs, as we
> normally do at ->runtime_suspend().
>
> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
(on R-Car Gen2, various Gen3, SH-Mobile AG5, R-Mobile A1, R-Mobile APE6,
RZ/A1, and RZ/A2)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2020-05-20 14:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 15:24 [PATCH 1/2] mmc: tmio: Further fixup runtime PM management at remove Ulf Hansson
2020-05-20 11:35 ` Ulf Hansson
2020-05-20 14:30 ` Geert Uytterhoeven [this message]
2020-05-20 15:18 ` Ulf Hansson
2020-05-20 15:49 ` Wolfram Sang
2020-05-20 18:19 ` Geert Uytterhoeven
2020-05-20 19:29 ` Geert Uytterhoeven
2020-05-20 20:32 ` Wolfram Sang
-- strict thread matches above, loose matches on Subject: below --
2020-05-15 14:04 Ulf Hansson
2020-05-15 15:02 ` Ulf Hansson
2020-05-18 20:02 ` Wolfram Sang
2020-05-19 13:56 ` Wolfram Sang
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