linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Enric Balletbo i Serra <enric.balletbo@collabora.com>
To: cwchoi00@gmail.com
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	stable <stable@vger.kernel.org>,
	kernel@collabora.com, Chanwoo Choi <cw00.choi@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	MyungJoo Ham <myungjoo.ham@samsung.com>,
	Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH v5] PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.
Date: Wed, 18 Jul 2018 11:04:36 +0200	[thread overview]
Message-ID: <91722bc1-6174-4a79-4bf6-4f2e91240676@collabora.com> (raw)
In-Reply-To: <CAGTfZH315DM0r4qxZ28rW=0SpWOJHjFoBij0=c8-OTG5BxeLAQ@mail.gmail.com>

Hi MyungJoo,

On 05/07/18 02:13, Chanwoo Choi wrote:
> Hi Enric,
> 
> 2018-07-04 17:45 GMT+09:00 Enric Balletbo i Serra
> <enric.balletbo@collabora.com>:
>> When the devfreq driver and the governor driver are built as modules,
>> the call to devfreq_add_device() or governor_store() fails because the
>> governor driver is not loaded at the time the devfreq driver loads. The
>> devfreq driver has a build dependency on the governor but also should
>> have a runtime dependency. We need to make sure that the governor driver
>> is loaded before the devfreq driver.
>>
>> This patch fixes this bug by adding a try_then_request_governor()
>> function. First tries to find the governor, and then, if it is not found,
>> it requests the module and tries again.
>>
>> Fixes: 1b5c1be2c88e (PM / devfreq: map devfreq drivers to governor using name)
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> ---
>>
>> Changes in v5:
>> - Requested by MyungJoo and Chanwoo.
>>   - Fix returning without the lock acquired after request_module.
>> - Requested by Chanwoo.
>>   - In request governor function check if governor name is NULL or not.
>>   - Remove some unrelated changes (added/removed some blank lines).
>>
>> Changes in v4:
>> - Kept "locked" devfreq_list from the return of find_devfreq_governor() to
>>   the unlock of governor_store(). Requested by MyungJoo Ham.
>>
>> Changes in v3:
>> - Remove unneded change in dev_err message.
>> - Fix err returned value in case to not find the governor.
>>
>> Changes in v2:
>> - Add a new function to request the module and call that function from
>>   devfreq_add_device and governor_store.
>>
>>  drivers/devfreq/devfreq.c | 53 ++++++++++++++++++++++++++++++++++++---
>>  1 file changed, 49 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 0b5b3abe054e..aa92fbf9f0dd 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
> 
> (snip)
> 
> Looks good to me.
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> 

I was expecting see also this patch in the pull request you did but I didn't
see. Is because of will be merged as a fix in current cycle? or has been forgotten?

Best regards,
 Enric


> Best Regards,
> Chanwoo Choi
> 

      reply	other threads:[~2018-07-18  9:04 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-04  8:45 [PATCH v5] PM / devfreq: Fix devfreq_add_device() when drivers are built as modules Enric Balletbo i Serra
2018-07-05  0:13 ` Chanwoo Choi
2018-07-18  9:04   ` Enric Balletbo i Serra [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=91722bc1-6174-4a79-4bf6-4f2e91240676@collabora.com \
    --to=enric.balletbo@collabora.com \
    --cc=cw00.choi@samsung.com \
    --cc=cwchoi00@gmail.com \
    --cc=kernel@collabora.com \
    --cc=kyungmin.park@samsung.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=myungjoo.ham@samsung.com \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).