On 5 May 2016 at 07:12, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > Some eMMCs set the partition switch timeout too low. > > Now typically eMMCs are considered a critical component (e.g. because > they store the root file system) and consequently are expected to be > reliable. Thus we can neglect the use case where eMMCs can't switch > reliably and we might want a lower timeout to facilitate speedy > recovery. > > Although we could employ a quirk for the cards that are affected (if > we could identify them all), as described above, there is little > benefit to having a low timeout, so instead simply set a minimum > timeout. > > The minimum is set to 300ms somewhat arbitrarily - the examples that > have been seen had a timeout of 10ms but were sometimes taking 60-70ms. > > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> Thanks, applied for next! Kind regards Uffe > --- > drivers/mmc/core/mmc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index f99c47e003fe..d4d1b77c1c1e 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -333,6 +333,9 @@ static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd) > } > } > > +/* Minimum partition switch timeout in milliseconds */ > +#define MMC_MIN_PART_SWITCH_TIME 300 > + > /* > * Decode extended CSD. > */ > @@ -397,6 +400,10 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) > > /* EXT_CSD value is in units of 10ms, but we store in ms */ > card->ext_csd.part_time = 10 * ext_csd[EXT_CSD_PART_SWITCH_TIME]; > + /* Some eMMC set the value too low so set a minimum */ > + if (card->ext_csd.part_time && > + card->ext_csd.part_time < MMC_MIN_PART_SWITCH_TIME) > + card->ext_csd.part_time = MMC_MIN_PART_SWITCH_TIME; > > /* Sleep / awake timeout in 100ns units */ > if (sa_shift > 0 && sa_shift <= 0x17) > -- > 1.9.1 > -- 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
