On Mon, August 26, 2013, Ulf Hansson wrote: > On 26 August 2013 08:39, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote: > > On Friday, August 23, 2013, Ulf Hansson wrote: > >> On 21 August 2013 14:42, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote: > >> > Currently there is no mmc_power_off() when resume failed. > >> > Somehow, state from mmc_power_on() will be kept. This change > >> > makes a pair with its use in case of failure. > >> > >> Hi Seungwon, > >> > >> To be safe, we can not power off, even if a resume failures. The > >> reason is that the bus/card/host is still available for sending > >> commands to it and those will then likely hang since IP controllers > >> internal registers is configured for "power off" state. > > Generally when host drivers get MMC_POWER_OFF, host doesn't gate clock for host running. > > MMC_POWER_ON/OFF is related to card side. So, I guess hanging isn't expected because host is kept > ready. > > At least for mmci host driver a hang may happen. Internal IP registers > needs to be set properly as done for MMC_POWER_ON mode, otherwise a > cmd can not be sent to the card without a potential hang, forever > waiting for an interrupt. I looked into the set_ios function of mmci host. Power for I/O bus lines are controlled there. Then unexpected occurrence from host may be possible. Host can raise interrupt though. Ok. Thanks, Seungwon Jeon > > I would be surprised if similar issues could not occur for other host > controllers/drivers. > > Kind regards > Ulf Hansson > > > > >> > >> Instead, we must leave the power off to be handled from the next > >> rescan work when the card is no longer properly "detected". For > >> NONREMOVABLE we will instead at error path try to do a > >> "power_restore_host". > > It might be needed graceful error handling. > > Ok, I'll consider further. > > > > Thanks, > > Seungwon Jeon > > > >> > >> Kind regards > >> Ulf Hansson > >> > >> > >> > > >> > Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx> > >> > --- > >> > drivers/mmc/core/mmc.c | 3 +++ > >> > drivers/mmc/core/sd.c | 3 +++ > >> > drivers/mmc/core/sdio.c | 3 +++ > >> > 3 files changed, 9 insertions(+), 0 deletions(-) > >> > > >> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > >> > index 6d02012..704a561 100644 > >> > --- a/drivers/mmc/core/mmc.c > >> > +++ b/drivers/mmc/core/mmc.c > >> > @@ -1536,6 +1536,9 @@ static int mmc_resume(struct mmc_host *host) > >> > mmc_power_up(host); > >> > mmc_select_voltage(host, host->ocr); > >> > err = mmc_init_card(host, host->ocr, host->card); > >> > + if (err) > >> > + mmc_power_off(host); > >> > + > >> > mmc_release_host(host); > >> > > >> > return err; > >> > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > >> > index 176d125..2690ae1 100644 > >> > --- a/drivers/mmc/core/sd.c > >> > +++ b/drivers/mmc/core/sd.c > >> > @@ -1099,6 +1099,9 @@ static int mmc_sd_resume(struct mmc_host *host) > >> > mmc_power_up(host); > >> > mmc_select_voltage(host, host->ocr); > >> > err = mmc_sd_init_card(host, host->ocr, host->card); > >> > + if (err) > >> > + mmc_power_off(host); > >> > + > >> > mmc_release_host(host); > >> > > >> > return err; > >> > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > >> > index 80d89cf..8c65669 100644 > >> > --- a/drivers/mmc/core/sdio.c > >> > +++ b/drivers/mmc/core/sdio.c > >> > @@ -1033,6 +1033,9 @@ static int mmc_sdio_resume(struct mmc_host *host) > >> > } > >> > } > >> > > >> > + if (err && !mmc_card_keep_power(host)) > >> > + mmc_power_off(host); > >> > + > >> > host->pm_flags &= ~MMC_PM_KEEP_POWER; > >> > return err; > >> > } > >> > -- > >> > 1.7.0.4 > >> > > >> > > >> > -- > >> > 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 > >> -- > >> 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 > > > > -- > > 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 > -- > 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 -- 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
