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 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
