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>
