On Wed, 22 Jun 2022 at 07:12, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
>
> We need runtime PM enabled early in probe before sdhci_setup_host() for
> sdhci_omap_set_capabilities(). But on the first runtime resume we must
> not call sdhci_runtime_resume_host() as sdhci_setup_host() has not been
> called yet. Let's check for an initialized controller like we already do
> for context restore to fix a lockdep warning.
Thanks for explaining the background to the problem. However, looking
a bit closer I am worried that the error path in ->probe() is broken
too.
It seems in the error path, at the label "err_rpm_put", there is a
call to pm_runtime_put_autosuspend(). This doesn't really guarantee
that the ->runtime_suspend() callback will be invoked, which I guess
is the assumption, don't you think?
That said, I wonder if it would not be easier to convert the ->probe()
function to make use of pm_runtime_get_noresume() and
pm_runtime_set_active() instead. In this way the ->probe() function
becomes responsible of turning on/off the resources "manually" that it
requires to probe (and when it fails to probe), while we can keep the
->runtime_suspend|resume() callbacks simpler.
Did that make sense to you?
Kind regards
Uffe
>
> Fixes: f433e8aac6b9 ("mmc: sdhci-omap: Implement PM runtime functions")
> Reported-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
>
> Changes since v1:
>
> - Add comments for why runtime PM is needed before sdhci_setup_host()
> as suggested by Adrian
>
> ---
> drivers/mmc/host/sdhci-omap.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
> --- a/drivers/mmc/host/sdhci-omap.c
> +++ b/drivers/mmc/host/sdhci-omap.c
> @@ -1298,8 +1298,9 @@ static int sdhci_omap_probe(struct platform_device *pdev)
> /*
> * omap_device_pm_domain has callbacks to enable the main
> * functional clock, interface clock and also configure the
> - * SYSCONFIG register of omap devices. The callback will be invoked
> - * as part of pm_runtime_get_sync.
> + * SYSCONFIG register to clear any boot loader set voltage
> + * capabilities before calling sdhci_setup_host(). The
> + * callback will be invoked as part of pm_runtime_get_sync.
> */
> pm_runtime_use_autosuspend(dev);
> pm_runtime_set_autosuspend_delay(dev, 50);
> @@ -1441,7 +1442,8 @@ static int __maybe_unused sdhci_omap_runtime_suspend(struct device *dev)
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
>
> - sdhci_runtime_suspend_host(host);
> + if (omap_host->con != -EINVAL)
> + sdhci_runtime_suspend_host(host);
>
> sdhci_omap_context_save(omap_host);
>
> @@ -1458,10 +1460,10 @@ static int __maybe_unused sdhci_omap_runtime_resume(struct device *dev)
>
> pinctrl_pm_select_default_state(dev);
>
> - if (omap_host->con != -EINVAL)
> + if (omap_host->con != -EINVAL) {
> sdhci_omap_context_restore(omap_host);
> -
> - sdhci_runtime_resume_host(host, 0);
> + sdhci_runtime_resume_host(host, 0);
> + }
>
> return 0;
> }
> --
> 2.36.1
