On Mon, Oct 22, 2012 at 1:54 PM, Felipe Balbi <balbi@xxxxxx> wrote: > The scheduler imposes a requirement to sched_clock() > which is to stop the clock during suspend, if we don't > do that IRQ threads will be rescheduled in the future > which might cause transfers to timeout depending on > how driver is written. > > This became an issue on OMAP when we converted omap-i2c.c > to use threaded IRQs, it turned out that depending on how > much time we spent on suspend, the I2C IRQ thread would > end up being rescheduled so far in the future that I2C > transfers would timeout and, because omap_hsmmc depends > on an I2C-connected device to detect if an MMC card is > inserted in the slot, our rootfs would just vanish. > > arch/arm/kernel/sched_clock.c already had an optional > implementation (sched_clock_needs_suspend()) which would > handle scheduler's requirement properly, what this patch > does is simply to make that implementation non-optional. > > This has been tested with beagleboard XM (OMAP3630) and > pandaboard rev A3 (OMAP4430). Suspend to RAM is now working > after this patch. > > Signed-off-by: Felipe Balbi <balbi@xxxxxx> After Russell explains so I get it: Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
