On Wed, Aug 27, 2014 at 3:26 PM, Stephen Boyd <sb...@codeaurora.org> wrote: > +Mark (author of change in question) > > On 08/27/14 14:27, Sonny Rao wrote: >> On Wed, Aug 27, 2014 at 2:19 PM, Olof Johansson <o...@lixom.net> wrote: >>> On Wed, Aug 27, 2014 at 2:03 PM, Sonny Rao <sonny...@chromium.org> wrote: >>>> This is a bug fix for using physical arch timers when >>>> the arch_timer_use_virtual boolean is false. It restores the >>>> arch_counter_get_cntpct() function after removal in >>>> >>>> 0d651e4e "clocksource: arch_timer: use virtual counters" >>>> >>>> and completes the implementation of memory mapped access for physical >>>> timers, so if a system is trying to use physical timers, it will >>>> function properly. >>>> >>>> Signed-off-by: Sonny Rao <sonny...@chromium.org> >>> Acked-by: Olof Johansson <o...@lixom.net> >>> >>> This should have a: >>> >>> Fixes: 0d651e4e65e9 ("clocksource: arch_timer: use virtual counters") >>> >>> tag too, and possibly cc stable? >> Ok, as far as stable goes, this patch wouldn't apply cleanly going all >> the way back to 0d651e4e65e9 >> As-is, it would need to go after 220069945b29 "clocksource: >> arch_timer: Add support for memory mapped timers" and there would need >> to be another, simpler, version that went between those two commits. >> >> So, I'm not sure what to do in this situation regarding stable?
Greg tends to make a best-effort, you'll find out when he looks at backporting and can reply with a "punt" or "here's the right patch" then. > Is there any reason why the virtual counter can't be read? Maybe we're > the hyp and we need to make sure we don't use the virtual timer so that > the guest can use it, but that doesn't have any effect on the usage of > the virtual counter for the clocksource. There are several cases where virtual is unusable -- in particular it might not have been configured properly (i.e. the phys/virt offset is at a bad value). -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/