On 25 May 2015 at 09:02, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 24-05-15 20:04, Michal Suchanek wrote: >> >> The function sunxi_mmc_oclk_onoff filters out the SDXC_LOW_POWER_ON flag >> but never sets it. >> >> Set SDXC_LOW_POWER_ON when oclk is disabled. > > > Nack, looking at the datasheet I do not thing this patch actually > does anything, according to the datasheet setting this bit to 1 results > in: "Turn off card clock when FSM in IDLE state", iow this does mmc clock > gating on idle automatically in hardware, since we completely disable the > clock on clock-off by clearing SDXC_CARD_CLOCK_ON setting this bit on > clock-off is a nop. > > We could consider actually setting this to safe power when setting the clock > on, for doing that it would be good to look at the android code and see if > it ever sets this bit and if so when. > > WRT CONFIG_MMC_CLKGATE we are probably better off using SDXC_LOW_POWER_ON > then that when it is enabled. So maybe we should set SDXC_LOW_POWER_ON > based on #ifdef WRT CONFIG_MMC_CLKGATE, and have some way to tell the > mmc core to not do clock gating on this host ? I am planning to remove the entire thing for CONFIG_MMC_CLKGATE, maybe it's time to do that now!? Most hosts use runtime PM to deal with clock gating at idle and browsing def configs tells me that CONFIG_MMC_CLKGATE isn't much used. Kind regards Uffe -- 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
