On Tue, 12 Nov 2019 at 21:49, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: > > On Tue, Nov 12, 2019 at 02:48:08PM +0100, Eugeniu Rosca wrote: > > From: Harish Jenny K N <harish_kandiga@xxxxxxxxxx> > > > > Enable MMC_CAP_ERASE capability in the driver to allow > > erase/discard/trim requests. > > > > Suggested-by: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> > > Signed-off-by: Harish Jenny K N <harish_kandiga@xxxxxxxxxx> > > [erosca: Forward-port and test on v5.4-rc7 using H3ULCB-KF: > > "blkdiscard /dev/mmcblk0" passes with this patch applied > > and complains otherwise: > > "BLKDISCARD ioctl failed: Operation not supported"] > > Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> > > Looks good to me. Just a generic question, probably more for Ulf: > > Why does this CAP_ERASE exist? As I understand, the driver only needs to > set the flag and no further handling is required. Why would a driver not > set this flag and not support erase/trim commands? I am working on removing the cap, altogether. Step by step, this is getting closer now. The main problem has been about busy detect timeouts, as an erase command may have a very long busy timeout. On the host side, they typically need to respect the cmd->busy_timeout for the request, and if it can't because of some HW limitation, it needs to set mmc->max_busy_timeout. Once that is fixed for all, we can drop CAP_ERASE. Kind regards Uffe
