Messages in this thread | | | Date | Thu, 19 Feb 2015 14:16:11 +0000 | Subject | Re: [PATCH v5 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer | From | Sudeep Holla <> |
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Hi Venkappa,
First of all, please make sure the relevant mailing list(ALKML in this case) and maintainers (MarcZ and Catalin as you are addressing him) are cc-ed, else there's every chance that the mail gets lost.
On Thu, Feb 19, 2015 at 1:03 PM, Venkappa Mala <venkappa.m@samsung.com> wrote: > Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha <at> arm.com> writes: > >> >> On 28/08/13 11:44, Sudeep KarkadaNagesha wrote: >> > From: Sudeep KarkadaNagesha <sudeep.karkadanagesha <at> arm.com> >> > >> > Few control settings done in architected timer as part of > initialisation >> > can be lost when CPU enters deeper power states. They need to be >> > re-initialised when the CPU is (warm)reset again. >> > >> > This patch adds CPU PM notifiers to do the timer initialisation on > warm >> > resets. It also save the event stream divider value calculated > during >> > cold reset and uses the same in warm reset path. >> > >> Ah, forgot to update the commit log. It's now updated: >> >> Few control settings done in architected timer as part of > initialisation >> can be lost when CPU enters deeper power states. They need to be >> restored when the CPU is (warm)reset again. >> >> This patch adds CPU PM notifiers to save the counter control register >> when entering low power modes and restore it when CPU exits low power. >> >> > Cc: Catalin Marinas <catalin.marinas <at> arm.com> >> > Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi <at> arm.com> >> > Reviewed-by: Will Deacon <will.deacon <at> arm.com> >> > Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha <at> > arm.com>
[...]
> Hello Catalin, > > I have noticed this patch merge in > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git > at >= linux-3.13.y branches. > > As part of ARMv7/ARMv8 vDSO experiments, i have tried to enable arch > timer in 3.10 branch but it is failed to boot like > "[1246696886.455361] swapper/0: 0] [c0] [c0] Calibrating delay > loop (skipped), value calculated using timer frequency.. 52.00 BogoMIPS > (lpj=260000)" > due to cntkctl context lost on both armv7/armv8 cases.However, it works > fine when I have pulled the patch to 3.10 branch. > > Perhaps, it will be good to have this patch in 3.10.y (LTS kernel) > branch as well. > is there any potential issue if we merge this patch or is it > intentional? >
Are you targeting this on ARM64 platform ? If so, I don't understand how is the arch timer context is lost as the cpuidle driver is not merge to 3.10 stable kernel ?
Regards, Sudeep
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