Re: [PATCH v3 0/5] clocksource: sun5i: Support parent clock rate changes

[Hans de Goede]

Hi,

On 20-03-15 21:56, Maxime Ripard wrote:
> Hi,
>
> On Fri, Mar 20, 2015 at 03:04:28PM +0100, Daniel Lezcano wrote:
> > On 03/19/2015 11:53 PM, Maxime Ripard wrote:
> > > Hi Daniel,
> > >
> > > On Thu, Mar 05, 2015 at 11:20:51AM +0100, Maxime Ripard wrote:
> > > > Hi,
> > > >
> > > > The Allwinner HS timers have the AHB clock as their parent
> > > > clock. Since this clock is shared with other devices, we could very
> > > > well have another driver requesting a rate change of that clock,
> > > > making our timer change frequency at the same time.
> > > >
> > > > This is especially true on the A31, where the DMA controller needs to
> > > > do such a rate change, making the HS timer unreliable at the time on
> > > > the A31.
> > > >
> > > > This serie makes some cleanups and implements clock notifiers to be
> > > > able to reflect such rate changes and make sure that the timer is
> > > > always working.
> > > >
> > > > Maxime
> > > >
> > > > Changes from v2:
> > > >    - Rebased on top of v4.0-rc1
> > > >    - Removed the local_irq_save/restore around clockevents_update_freq
> > > >
> > > > Changes from v1:
> > > >    - Changed the interrupt name to its previous value
> > > >
> > > > Maxime Ripard (5):
> > > >    clocksource: sun5i: Switch to request_irq
> > > >    clocksource: sun5i: Use of_io_request_and_map
> > > >    clocksource: sun5i: Remove sched_clock
> > > >    clocksource: sun5i: Refactor the current code
> > > >    clocksource: sun5i: Add clock notifiers
> > >
> > > Have these patches been merged?
> > >
> > > If not, it woulde be great if the third one ("clocksource: sun5i:
> > > Remove sched_clock") was merged for 4.0.
> > >
> > > The sched_clock we use on some system is this timer's, and since we
> > > started using cpufreq, the cpu clock (that is one of the timer's clock
> > > indirect parent) now changes, along with the actual sched_clock rate.
> > >
> > > We can safely remove the sched_clock on those systems, since we have
> > > other reliable sched_clock in the system.
> >
> > Ok, I applied the patch for v4.0-rc5 but I had to fix a conflict and change
> > the changelog.
>
> It looks fine.
>
> Note that the rest of the serie should also be merged, this is just a
> temporary measure for 4.0.
>
> > Mind to test it works ?
> >
> > git.linaro.org/people/daniel.lezcano/linux.git clockevents/v4.0-rc4
>
> Unfortunately, I won't have access to my boards for ~10 days due to
> travel to ELC. Chen-Yu, Hans, could you test this and see if it works?

I've just given this a test run on an A20 board, using the dmesg
timestamps are off reproducer discussed before, and the problem no
longer reproduces on the clockevents/4.0-rc4 branch, and everything
else still seems to work fine.

Regards,

Hans
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