Re: [PATCH 1/1] Cpufreq: Keep cpufreq sysfs nodes across S2RAM/S2DISK when using intel_pstate driver.
From: Rafael J. Wysocki
Date: Mon Sep 29 2014 - 19:24:21 EST
On Monday, September 29, 2014 01:20:44 AM Viresh Kumar wrote:
> Sorry for being late on this. Was away for a week for Linaro Connect followed
> by a week of vacations :(
> On 18 September 2014 00:03, Lan Tianyu <tianyu.lan@xxxxxxxxx> wrote:
> > Cpufreq core introduces cpufreq_suspended flag to let cpufreq sysfs nodes
> > across S2RAM/S2DISK. But the flag is only set in the cpufreq_suspend()
> > for cpufreq drivers which have target or target_index callback. This
> > skips intel_pstate driver. This patch is to set the flag before checking
> > target or target_index callback.
> Oh yes, this looks to be the right thing to do..
> > Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> > ---
> > drivers/cpufreq/cpufreq.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index d9fdedd..eb9bb78 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -1656,6 +1656,8 @@ void cpufreq_suspend(void)
> > if (!cpufreq_driver)
> > return;
> > + cpufreq_suspended = true;
> > +
> > if (!has_target())
> > return;
> > @@ -1670,8 +1672,6 @@ void cpufreq_suspend(void)
> > pr_err("%s: Failed to suspend driver: %p\n", __func__,
> > policy);
> > }
> > -
> > - cpufreq_suspended = true;
> But this change is buggy.. Because you are updating 'cpufreq_suspended'
> before actually stopping the governor, any calls to __cpufreq_governor()
> will be converted to NO-operations because of this in __cpufreq_governor():
> /* Don't start any governor operations if we are entering suspend */
> if (cpufreq_suspended)
> return 0;
> And so the governor's will never stop :(
> So you need to keep the above line where it was :)
OK, so please send a fix for that against the Linus' tree.
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/