[PATCH] mmc: Do not send status of send_status is false

Marek Vasut marex at denx.de
Fri Jul 15 01:58:24 CEST 2022

Commit 44645f87de5 ("mmc: Fix mmc_switch excessive timeout") introduced
a side effect where CMD13 SEND_STATUS is issued in case mmc_wait_dat0()
does not return -ENOSYS and $send_status is not set. This happens on all
hardware which does implement .mmc_wait_dat0 callback, e.g. i.MX8M .

This leads to lengthy timeout before booting OS in case of eMMC in one
of the HS200/HS400 modes, since the card cannot respond to CMD13 while
downgrading from HS200/HS400 to regular HS mode.

Fix this by adding the missing conditional.

Fixes: 44645f87de5 ("mmc: Fix mmc_switch excessive timeout")
Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Jaehoon Chung <jh80.chung at samsung.com>
Cc: Kirill Kapranov <kirill.kapranov at compulab.co.il>
Cc: Marek Behún <marek.behun at nic.cz>
Cc: Pantelis Antoniou <panto at antoniou-consulting.com>
Cc: Ye Li <ye.li at nxp.com>
 drivers/mmc/mmc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 12d29da528a..b62baca8457 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -831,6 +831,9 @@ static int __mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value,
 		return 0;
+	if (!send_status)
+		return 0;
 	/* Finally wait until the card is ready or indicates a failure
 	 * to switch. It doesn't hurt to use CMD13 here even if send_status
 	 * is false, because by now (after 'timeout_ms' ms) the bus should be

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