On 24.06.2014 00:19, Kevin Hilman wrote: > Doug Anderson <dianders@xxxxxxxxxxxx> writes: > > [...] > >> On Fri, Jun 20, 2014 at 4:59 PM, Tomasz Figa <tomasz.figa@xxxxxxxxx> wrote: >>> >>> I'm not sure noirq is going to work correctly, at least not with current >>> callbacks. I can see a call to clk_prepare_enable() there which needs to >>> acquire a mutex. >> >> Nice catch, thanks! :) >> >> OK, looking at that now. Interestingly this doesn't seem to cause us >> problems in our ChromeOS 3.8 tree. I just tried enabling: >> CONFIG_DEBUG_ATOMIC_SLEEP=y >> >> ...and confirmed that I got it on right: >> >> # zgrep -i atomic /proc/config.gz >> CONFIG_DEBUG_ATOMIC_SLEEP=y >> >> I can suspend/resume with no problems. My bet is that it works fine because: >> >> * resume_noirq is not considered "atomic" in the sense enforced by >> CONFIG_DEBUG_ATOMIC_SLEEP (at least not in 3.8--I haven't tried on >> ToT) > > The reason is because "noirq" in the suspend/resume path actually means > no *device* IRQs for that specific device. > > It's often assumed that the "noirq" callbacks are called with *all* > interrupts disabled, but that's not the case. Only the IRQs for that > specific device are disabled when its noirq callbacks run. Thanks for clarifying this. This means that we should be fine with the noirq variant then. Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
