On 21 April 2017 at 12:08, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > The SDIO card state might be being preserved during hibernation, for > example a SDIO wifi card supporting WOWLAN. That state will be lost if an > SDIO reset is done. One way to avoid that would be to build mmc core as a > module and simply not load it until after attempting to restore the > hibernation image. However that won't work if the hibernation image is > stored on eMMC which, of course, requires mmc core. I don't follow here. Are you saying the SDIO card is kept powered in hibernation, as to be able to support WOWLAN, right? Then, it feels plain wrong the mmc_rescan() tries to re-initialize it. That should never happen, unless something is broken of course. Kind regards Uffe > > It is assumed on such systems that the platform will power cycle the SDIO > card or not as necessary so that the SDIO reset is not needed. Add a > capability flag to reflect that and use it to skip the SDIO reset at scan > time. > > Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > --- > drivers/mmc/core/core.c | 6 +++++- > include/linux/mmc/host.h | 1 + > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 6987976252ad..178e23bf0c30 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -2639,8 +2639,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq) > * if the card is being re-initialized, just send it. CMD52 > * should be ignored by SD/eMMC cards. > * Skip it if we already know that we do not support SDIO commands > + * Also skip it if we know this host controller has a SDIO card that > + * needs to be able to restore from hibernation without losing the card > + * state e.g. an SDIO wifi card supporting WOWLAN. > */ > - if (!(host->caps2 & MMC_CAP2_NO_SDIO)) > + if (!(host->caps2 & MMC_CAP2_NO_SDIO) && > + !(host->caps2 & MMC_CAP2_NO_SDIO_RESET)) > sdio_reset(host); > > mmc_go_idle(host); > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 78c544e296cd..187a7ba41364 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -281,6 +281,7 @@ struct mmc_host { > u32 caps2; /* More host capabilities */ > > #define MMC_CAP2_BOOTPART_NOACC (1 << 0) /* Boot partition no access */ > +#define MMC_CAP2_NO_SDIO_RESET (1 << 1) /* Do not SDIO reset at scan */ > #define MMC_CAP2_FULL_PWR_CYCLE (1 << 2) /* Can do full power cycle */ > #define MMC_CAP2_HS200_1_8V_SDR (1 << 5) /* can support */ > #define MMC_CAP2_HS200_1_2V_SDR (1 << 6) /* can support */ > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html