Messages in this thread | | | Date | Mon, 17 Jun 2013 11:47:11 +0900 | Subject | Re: [PATCH/RFC] arm: arch_timer: Do not set C3STOP in case CPU_IDLE=n | From | Magnus Damm <> |
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Hi Simon,
On Mon, Jun 17, 2013 at 11:13 AM, Simon Horman <horms@verge.net.au> wrote: > On Mon, Jun 17, 2013 at 09:20:56AM +0900, Magnus Damm wrote: >> From: Magnus Damm <damm@opensource.se> >> >> Modify the ARM architected timer driver to not set C3STOP >> in case CPU_IDLE is disabled. This is a short term fix that >> allows use of high resolution timers even though no additional >> clock event is registered. >> >> Not-really-Signed-off-by: Magnus Damm <damm@opensource.se> >> --- >> >> If someone cares about this case then perhaps it should be >> moved up to the clock event main code. The same issue should >> in theory trigger on all architectures, perhaps x86 people >> hunting for low latency may try to disable CPU_IDLE? >> >> I propose carrying this patch locally to enable high resolution >> timers until CPU_IDLE and an additional clock event is supported. >> >> Observed on r8a73a4 and APE6EVM. > > Hi Magnus, > > Is this patch intended to be picked up by me for the LTSI-3.4.25 based > backports that live in my renesas-backports tree?
Yes, correct.
The patch was mainly written to satisfy a feature request for your backports, but I noticed that the same issue exists in upstream as well.
Ideally I'd like to use the same code for the backport and upstream, but I am not sure if anyone in upstream really cares. The more long term solution is obviously to install a second clock event, perhaps that's good enough.
> If so, could you clearly state this (below the '---' is fine) and > include a proper Sob line to indicate that it is fit to be merged > even if that merge is not into mainline.
Sure, but I'd like to hear opinions from other people before resending. I will follow your recommendation in next version.
Thanks,
/ magnus
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