From: Wolfram Sang <wsa+renesas@sang-engineering.com> stable inclusion from linux-4.19.198 commit fdfa7b1008d9f7258818221d7500da9e0f848f50 -------------------------------- 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: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Fixes: bd11e8bd03ca ("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-engineerin... Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/mmc/core/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 798bcb65b4df4..e340791a8eab3 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -980,11 +980,14 @@ 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; } -- 2.25.1