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. Kevin -- 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
