Re: [PATCH 1/2] mmc: tmio: Further fixup runtime PM management at remove

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

[-- Attachment #1: Type: text/plain, Size: 1208 bytes --]

On Fri, May 15, 2020 at 04:04:45PM +0200, Ulf Hansson 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.
> 
> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Works fine on my Lager board, too. Imbalance is gone when rebinding, and
I can access large files on the SD card.

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]