Re: [RFC][PATCH] pinctrl: Rework driver_deferred_probe_check_state() evaluation since default timeout has changed

[Greg Kroah-Hartman]

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: linux-pm@xxxxxxxxxxxxxxx
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Cc: Thierry Reding <treding@xxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
> Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
> Cc: Todd Kjos <tkjos@xxxxxxxxxx>
> Cc: Len Brown <len.brown@xxxxxxxxx>
> Cc: Pavel Machek <pavel@xxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Cc: Rob Herring <robh@xxxxxxxxxx>
> 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 <thierry.reding@xxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> ---
>  drivers/pinctrl/devicetree.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>