From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: John Stultz <john.stultz@linaro.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
Rob Herring <robh@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>, Pavel Machek <pavel@ucw.cz>,
Len Brown <len.brown@intel.com>, Todd Kjos <tkjos@google.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>,
Thierry Reding <treding@nvidia.com>,
Linus Walleij <linus.walleij@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-pm@vger.kernel.org
Subject: Re: [PATCH v4 1/6] driver core: Fix driver_deferred_probe_check_state() logic
Date: Thu, 20 Feb 2020 07:55:03 -0800 [thread overview]
Message-ID: <20200220155503.GD955802@ripper> (raw)
In-Reply-To: <20200220050440.45878-2-john.stultz@linaro.org>
On Wed 19 Feb 21:04 PST 2020, John Stultz wrote:
> driver_deferred_probe_check_state() has some uninituitive behavior.
>
> * From boot to late_initcall, it returns -EPROBE_DEFER
>
> * From late_initcall to the deferred_probe_timeout (if set)
> it returns -ENODEV
>
> * If the deferred_probe_timeout it set, after it fires, it
> returns -ETIMEDOUT
>
> This is a bit confusing, as its useful to have the function
> return -EPROBE_DEFER while the timeout is still running. This
> behavior has resulted in the somwhat duplicative
> driver_deferred_probe_check_state_continue() function being
> added.
>
> Thus this patch tries to improve the logic, so that it behaves
> as such:
>
> * If deferred_probe_timeout is set, it returns -EPROBE_DEFER
> until the timeout, afterwhich it returns -ETIMEDOUT.
>
> * If deferred_probe_timeout is not set (-1), it returns
> -EPROBE_DEFER until late_initcall, after which it returns
>
> This will make the deferred_probe_timeout value much more
> functional, and will allow us to consolidate the
> driver_deferred_probe_check_state() and
> driver_deferred_probe_check_state_continue() logic in a later
> patch.
>
> Cc: Rob Herring <robh@kernel.org>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Kevin Hilman <khilman@kernel.org>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Len Brown <len.brown@intel.com>
> Cc: Todd Kjos <tkjos@google.com>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Liam Girdwood <lgirdwood@gmail.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Thierry Reding <treding@nvidia.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-pm@vger.kernel.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Change-Id: I8349b7a403ce8cbce485ea0a0a5512fddffb635c
Please drop the Change-Id.
> ---
> v4:
> * Simplified logic suggested by Andy Shevchenko
> * Clarified commit message to focus on logic change
> ---
> drivers/base/dd.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index b25bcab2a26b..bb383dca39c1 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -237,7 +237,7 @@ __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
>
> static int __driver_deferred_probe_check_state(struct device *dev)
> {
> - if (!initcalls_done)
> + if (!initcalls_done || deferred_probe_timeout > 0)
> return -EPROBE_DEFER;
>
> if (!deferred_probe_timeout) {
> @@ -252,9 +252,11 @@ static int __driver_deferred_probe_check_state(struct device *dev)
> * driver_deferred_probe_check_state() - Check deferred probe state
> * @dev: device to check
> *
> - * Returns -ENODEV if init is done and all built-in drivers have had a chance
> - * to probe (i.e. initcalls are done), -ETIMEDOUT if deferred probe debug
> - * timeout has expired, or -EPROBE_DEFER if none of those conditions are met.
> + * Returnes -EPROBE_DEFER if initcalls have not completed, or the deferred
As pointed out by Rafael, this should be Return:
With that addressed, you have my
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Regards,
Bjorn
> + * probe timeout is set, but not expried.
> + * Returns -ETIMEDOUT if the probe timeout was set and has expired.
> + * Returns -ENODEV if initcalls have completed and the deferred probe timeout
> + * was not set.
> *
> * Drivers or subsystems can opt-in to calling this function instead of directly
> * returning -EPROBE_DEFER.
> --
> 2.17.1
>
next prev parent reply other threads:[~2020-02-20 15:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 5:04 [PATCH v4 0/6] driver core: Try to improve and cleanup driver_deferred_probe_check_state() John Stultz
2020-02-20 5:04 ` [PATCH v4 1/6] driver core: Fix driver_deferred_probe_check_state() logic John Stultz
2020-02-20 10:28 ` Rafael J. Wysocki
2020-02-20 15:55 ` Bjorn Andersson [this message]
2020-02-20 23:40 ` Pavel Machek
2020-02-20 23:42 ` John Stultz
2020-02-20 5:04 ` [PATCH v4 2/6] driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set John Stultz
2020-02-20 10:36 ` Rafael J. Wysocki
2020-02-20 15:55 ` Bjorn Andersson
2020-02-20 5:04 ` [PATCH v4 3/6] pinctrl: Remove use of driver_deferred_probe_check_state_continue() John Stultz
2020-02-21 15:21 ` Linus Walleij
2020-02-21 17:19 ` John Stultz
2020-02-20 5:04 ` [PATCH v4 4/6] driver core: Remove driver_deferred_probe_check_state_continue() John Stultz
2020-02-20 10:38 ` Rafael J. Wysocki
2020-02-20 15:59 ` Bjorn Andersson
2020-02-20 5:04 ` [PATCH v4 5/6] driver core: Rename deferred_probe_timeout and make it global John Stultz
2020-02-20 10:42 ` Rafael J. Wysocki
2020-02-20 16:00 ` Bjorn Andersson
2020-02-20 5:04 ` [PATCH v4 6/6] regulator: Use driver_deferred_probe_timeout for regulator_init_complete_work John Stultz
2020-02-20 16:05 ` Bjorn Andersson
2020-02-20 10:15 ` [PATCH v4 0/6] driver core: Try to improve and cleanup driver_deferred_probe_check_state() Rafael J. Wysocki
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