Thanks Shawn. Please help to check the below in the mmc_blk_rw_rq_prep: if (do_rel_wr) mmc_apply_rel_rw(brq, card, req); I think we need to set the do_rel_wr to false( at the beginning of this function) if the card does not support the CMD23. The above code is executed before the "if ((md->flags & MMC_BLK_CMD23)" code. Thanks, Yong Li ---------------------------------------- > Subject: Re: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23 > To: sdliyong@xxxxxxxxx; chris@xxxxxxxxxx; ulf.hansson@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > CC: shawn.lin@xxxxxxxxxxxxxx > From: shawn.lin@xxxxxxxxxxxxxx > Date: Fri, 14 Aug 2015 16:13:02 +0800 > > 在 2015/8/14 15:30, sdliyong@xxxxxxxxx 写道: >> From: Yong Li <sdliyong@xxxxxxxxx> >> >> Signed-off-by: Yong Li <sdliyong@xxxxxxxxx> >> --- >> drivers/mmc/card/block.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c >> index 452782b..d9e3c45 100644 >> --- a/drivers/mmc/card/block.c >> +++ b/drivers/mmc/card/block.c >> @@ -1366,7 +1366,8 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, >> bool do_rel_wr = ((req->cmd_flags & REQ_FUA) || >> (req->cmd_flags & REQ_META)) && >> (rq_data_dir(req) == WRITE) && >> - (md->flags & MMC_BLK_REL_WR); >> + (md->flags & MMC_BLK_REL_WR) && >> + !(card->quirks & MMC_QUIRK_BLK_NO_CMD23); > > Hi Yong, > > pls check that code below. > > MMC_BLK_REL_WR will not be enabled if we know this card CANNOT support > CMD23 form SCR. AND, "card->quirks & MMC_QUIRK_BLK_NO_CMD23" would be > checked here as well. So I think your code is unnecessary. > > if ((md->flags & MMC_BLK_CMD23) && mmc_op_multi(brq->cmd.opcode) && > (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) || > do_data_tag)) { > brq->sbc.opcode = MMC_SET_BLOCK_COUNT; > brq->sbc.arg = brq->data.blocks | > (do_rel_wr ? (1 << 31) : 0) | > (do_data_tag ? (1 << 29) : 0); > brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC; > brq->mrq.sbc = &brq->sbc; > } > > Thanks. > Shawn > >> >> memset(brq, 0, sizeof(struct mmc_blk_request)); >> brq->mrq.cmd = &brq->cmd; >> > > > -- > Shawn Lin > ��.n��������+%������w��{.n�����{��i��)��jg��������ݢj����G�������j:+v���w�m������w�������h�����٥