On Sat, Aug 08, 2020 at 04:35:12AM +0000, John Stultz wrote:
> In commit bec6c0ecb243 ("pinctrl: Remove use of
> driver_deferred_probe_check_state_continue()"), we removed the
> use of driver_deferred_probe_check_state_continue() which
> effectively never returned -ETIMED_OUT, with the
> driver_deferred_probe_check_state() function that had been
> reworked to properly return ETIMED_OUT when the deferred probe
> timeout expired. Along with that change, we set the default
> timeout to 30 seconds.
>
> However, since moving the timeout to 30 seconds caused some
> issues for some users with optional dt links, we set the
> default timeout back to zero - see commit ce68929f07de ("driver
> core: Revert default driver_deferred_probe_timeout value to 0")
>
> This in essence changed the behavior of the pinctrl's usage
> of driver_deferred_probe_check_state(), as it now would return
> ETIMED_OUT by default. Thierry reported this caused problems with
> resume on tegra platforms.
>
> Thus this patch tweaks the pinctrl logic so that it behaves as
> before. If modules are enabled, we'll only return EPROBE_DEFERRED
> while we're missing drivers linked in the DT.
>
> Cc: [email protected]
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Linus Walleij <[email protected]>
> Cc: Thierry Reding <[email protected]>
> Cc: Mark Brown <[email protected]>
> Cc: Liam Girdwood <[email protected]>
> Cc: Bjorn Andersson <[email protected]>
> Cc: Saravana Kannan <[email protected]>
> Cc: Todd Kjos <[email protected]>
> Cc: Len Brown <[email protected]>
> Cc: Pavel Machek <[email protected]>
> Cc: Ulf Hansson <[email protected]>
> Cc: Kevin Hilman <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Rob Herring <[email protected]>
> Fixes: bec6c0ecb243 ("pinctrl: Remove use of
> driver_deferred_probe_check_state_continue()")
> Fixes: ce68929f07de ("driver core: Revert default
> driver_deferred_probe_timeout value to 0")
> Reported-by: Thierry Reding <[email protected]>
> Signed-off-by: John Stultz <[email protected]>
> ---
> drivers/pinctrl/devicetree.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
> index c6fe7d64c913..09ddf567ccb4 100644
> --- a/drivers/pinctrl/devicetree.c
> +++ b/drivers/pinctrl/devicetree.c
> @@ -129,9 +129,8 @@ static int dt_to_map_one_config(struct pinctrl *p,
> if (!np_pctldev || of_node_is_root(np_pctldev)) {
> of_node_put(np_pctldev);
> ret = driver_deferred_probe_check_state(p->dev);
> - /* keep deferring if modules are enabled unless we've
> timed out */
> - if (IS_ENABLED(CONFIG_MODULES) && !allow_default &&
> - (ret == -ENODEV))
> + /* keep deferring if modules are enabled */
> + if (IS_ENABLED(CONFIG_MODULES) && !allow_default)
> ret = -EPROBE_DEFER;
> return ret;
> }
I posted almost exactly the same patch a couple of days ago since I
hadn't noticed this:
https://patchwork.ozlabs.org/project/linux-gpio/patch/[email protected]/
I like that slightly better because it keeps the "ret < 0" condition,
which I think is perhaps a bit more future-proof. Thinking about it, I'm
not sure your version above is entirely correct. For example if the call
to driver_deferred_probe_check_state() were to ever return 0, we might
still be returning -EPROBE_DEFER here.
That's not something that happens currently, but I suspect that these
implications will be easy to overlook.
Actually... I think it might be best to just bring back (albeit perhaps
in a modified form) driver_deferred_probe_check_state_continue() because
we're now basically doing exactly what that was supposed to do: special-
casing the case where we do want to continue returning -EPROBE_DEFER in
some special cases.
Thierry
signature.asc
Description: PGP signature
