Hi Arnd, On Wed, Dec 29, 2010 at 12:35 PM, Arnd Hannemann <arnd@xxxxxxxxxx> wrote: > So you suggest to don't set MMC_CAP_POWER_OFF_CARD for the boards which > keep the card powered Yes, if you can't power off your card, it doesn't make a lot of sense to set it MMC_CAP_POWER_OFF_CARD. If the reason is to notify the host controller, via runtime PM, to disable the clock to the card, we need first to see that it works (have you tested it ? how ?): currently there are no host controllers which employ runtime PM. It looks like sdhci is about to, but it is still not clear how exactly - it is just being discussed. Moreover, it seems that host controllers will ignore the card's runtime PM status, in order to allow them to independently manage their runtime PM status (and by that disable clocks more aggressively). So I'd wait to see how those discussions evolve (or jump in and have my use case considered) but before that it won't make a lot of sense to add MMC_CAP_POWER_OFF_CARD for cards that are always powered on, because it is currently still not clear that it will yield any benefit. >> For example, the wl1271 card has asynchronous interrupts (via external >> irq) so we can safely stop its clock on inactivity. >> >> Do you know if that's possible with your card as well ? > > I don't think so, the card is a normal SDIO card which plugs into a normal > MMC/SD slot, no extra pins or such. However SDIO IRQs are available, but you > don't mean that, do you? Some cards do support asynchronous SDIO IRQs (do you know if yours too btw ?). How this is going to be safely employed is still in discussions... Thanks, Ohad. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
