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Commit 95a74030 authored by Wolfram Sang's avatar Wolfram Sang Committed by Greg Kroah-Hartman
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mmc: core: clear flags before allowing to retune 



commit 77347eda64ed5c9383961d1de9165f9d0b7d8df6 upstream.

It might be that something goes wrong during tuning so the MMC core will
immediately trigger a retune. In our case it was:

 - we sent a tuning block
 - there was an error so we need to send an abort cmd to the eMMC
 - the abort cmd had a CRC error
 - retune was set by the MMC core

This lead to a vicious circle causing a performance regression of 75%.
So, clear retuning flags before we enable retuning to start with a known
cleared state.

Reported-by Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Suggested-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: bd11e8bd ("mmc: core: Flag re-tuning is needed on CRC errors")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210624151616.38770-2-wsa+renesas@sang-engineering.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3438609e

drivers/mmc/core/core.c

+5 −2
Original line number Diff line number Diff line
@@ -1171,11 +1171,14 @@ int mmc_execute_tuning(struct mmc_card *card) 


	err = host->ops->execute_tuning(host, opcode);



	if (err)

	if (err) {

		pr_err("%s: tuning execution failed: %d\n",

			mmc_hostname(host), err);

	else

	} else {

		host->retune_now = 0;

		host->need_retune = 0;

		mmc_retune_enable(host);

	}



	return err;

}