From: slash.tmp@free•fr (Mason)
To: linux-arm-kernel@lists•infradead.org
Subject: schedule_timeout sleeps too long after dividing CPU frequency
Date: Wed, 20 May 2015 21:34:16 +0200 [thread overview]
Message-ID: <555CE1B8.70205@free.fr> (raw)
In-Reply-To: <12867692.bB1EJHiPzq@wuerfel>
On 20/05/2015 20:50, Arnd Bergmann wrote:
> On Wednesday 20 May 2015 18:21:45 Mason wrote:
>>
>> On 18/05/2015 13:54, Russell King - ARM Linux wrote:
>>
>>> For a SoC where WFI is not programmed to cause anything other than
>>> the architecture specified dormant behaviour, WFI will not cause the
>>> TWD to stop.
>>
>> According to the hardware engineers, my SoC does not support any
>> low-power modes.
>>
>> But I didn't see the "clean" way to make the kernel aware of this.
>> Is this an acceptable patch? (I have my doubts.)
>
> No, this is clearly broken.
I don't see it. Could you be more explicit?
>> diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
>> index 6591e26..300f13a 100644
>> --- a/arch/arm/kernel/smp_twd.c
>> +++ b/arch/arm/kernel/smp_twd.c
>> @@ -295,6 +295,10 @@ static void twd_timer_setup(void)
>> clk->name = "local_timer";
>> clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
>> CLOCK_EVT_FEAT_C3STOP;
>> +#ifdef CONFIG_TANGOX
>> + /*** Tango does not implement low power modes ***/
>> + clk->features &= ~CLOCK_EVT_FEAT_C3STOP;
>> +#endif
>> clk->rating = 350;
>> clk->set_mode = twd_set_mode;
>> clk->set_next_event = twd_set_next_event;
>
> This will disable the feature on all machines that are configured
> in the kernel.
What do you mean, "disable the feature"?
My proposed patch doesn't change the default, which is to set
CLOCK_EVT_FEAT_C3STOP unconditionally for all machines.
And then only for some platforms (in this case only TANGOX)
CLOCK_EVT_FEAT_C3STOP is *removed* from the features list.
Regards.
next prev parent reply other threads:[~2015-05-20 19:34 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-12 14:32 schedule_timeout sleeps too long after dividing CPU frequency Mason
2015-05-12 14:46 ` Viresh Kumar
2015-05-12 15:14 ` Mason
2015-05-12 15:50 ` Russell King - ARM Linux
2015-05-12 16:14 ` Mason
2015-05-13 16:51 ` Mason
2015-05-14 2:13 ` Viresh Kumar
2015-05-14 11:22 ` Mason
2015-05-14 11:54 ` Viresh Kumar
2015-05-14 13:06 ` Mason
2015-05-14 13:53 ` Russell King - ARM Linux
2015-05-14 14:51 ` Mason
2015-05-14 13:59 ` Viresh Kumar
2015-05-14 14:38 ` Viresh Kumar
2015-05-14 14:42 ` Russell King - ARM Linux
2015-05-15 9:29 ` Mason
2015-05-15 9:51 ` Russell King - ARM Linux
2015-05-15 10:01 ` Viresh Kumar
2015-05-15 10:36 ` Mason
2015-05-15 11:58 ` Russell King - ARM Linux
2015-05-15 12:45 ` Mason
2015-05-15 13:15 ` Russell King - ARM Linux
2015-05-15 13:58 ` Mason
2015-05-15 18:35 ` Mason
2015-05-18 11:24 ` Mason
2015-05-18 11:54 ` Russell King - ARM Linux
2015-05-20 16:21 ` Mason
2015-05-20 18:50 ` Arnd Bergmann
2015-05-20 19:34 ` Mason [this message]
2015-05-20 20:14 ` Russell King - ARM Linux
2015-05-20 20:41 ` Mason
2015-05-20 20:52 ` Arnd Bergmann
2015-05-20 21:56 ` Mason
2015-05-20 22:18 ` Arnd Bergmann
2015-05-21 12:35 ` Mason
2015-05-20 23:14 ` Russell King - ARM Linux
2015-05-21 9:56 ` Mason
2015-05-21 10:20 ` Russell King - ARM Linux
2015-05-14 14:48 ` Mason
2015-05-15 4:16 ` Viresh Kumar
2015-05-15 5:07 ` Viresh Kumar
2015-05-15 9:00 ` Russell King - ARM Linux
2015-05-15 9:21 ` Mason
2015-05-15 10:11 ` Mason
2015-05-12 15:23 ` Russell King - ARM Linux
2015-05-12 16:03 ` Mason
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=555CE1B8.70205@free.fr \
--to=slash.tmp@free$(echo .)fr \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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