Hi Arnd, On Tue, Dec 28, 2010 at 4:03 PM, Arnd Hannemann <arnd@xxxxxxxxxx> wrote: >> Do you mean that your card is always powered on regardless of >> mmc_power_off() invocations ? > > Yes, it seems so. Ok, thanks for letting us know. It bothered me that we didn't understand the issue you had, but now it seems that MMC_CAP_POWER_OFF_CARD is the right solution for you as well. > Even if the card is kept powered, when mmc_power_off() is called, the > host controller will stop the SD bus clock. So I believe at least some > power is saved this way and MMC_CAP_POWER_OFF_CARD makes sense? Well, with some SDIO cards, the host controller can use the recently added aggressive clock gating framework to stop the clock on inactivity, and not wait until the card is powered off. Currently that clock gating framework is still disabled for SDIO cards, but this is just temporary until we sort out how to use it safely for SDIO as well. 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 ? 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
