Hi Ohad, Am 28.12.2010 15:24, schrieb Ohad Ben-Cohen: >>> 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. So you suggest to don't set MMC_CAP_POWER_OFF_CARD for the boards which keep the card powered, but instead wait for the clock gating framework? > 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? Thanks, Arnd -- 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
