The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 77347eda64ed5c9383961d1de9165f9d0b7d8df6 Mon Sep 17 00:00:00 2001
From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Date: Thu, 24 Jun 2021 17:16:14 +0200
Subject: [PATCH] mmc: core: clear flags before allowing to retune
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@xxxxxxxxxxx>
Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Fixes: bd11e8bd03ca ("mmc: core: Flag re-tuning is needed on CRC errors")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20210624151616.38770-2-wsa+renesas@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index b039dcff17f8..95fedcf56e4a 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -937,11 +937,14 @@ 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;
}
