> On 02.03.23 3:43 PM, Ulf Hansson wrote: > > REQ_FUA is in general supported for eMMC cards, which translates into > > so called "reliable writes". To support these write operations, the > > CMD23 (MMC_CAP_CMD23), needs to be supported by the mmc host too, > > which is common but not always the case. > > > > For some eMMC devices, it has been reported that reliable writes are > > quite costly, leading to performance degradations. > > > > In a way to improve the situation, let's avoid announcing REQ_FUA > > support if the eMMC supports an internal cache, as that allows us to > > rely solely on flush-requests (REQ_OP_FLUSH) instead, which seems to be a > lot cheaper. > > Note that, those mmc hosts that lacks CMD23 support are already using > > this type of configuration, whatever that could mean. > > > > Reported-by: Wenchao Chen<wenchao.chen666@xxxxxxxxx> > > Signed-off-by: Ulf Hansson<ulf.hansson@xxxxxxxxxx> > Acked-by: Bean Huo <beanhuo@xxxxxxxxxx> Acked-by: Avri Altman <avri.altman@xxxxxxx> Another option might be, allowing to report "broken_fua", should the platform owner chooses to, much like scsi does per sdev. Thanks, Avri
