mmc: sdhci-pci-gli: increase 1.8V regulator wait

BugLink: https://bugs.launchpad.net/bugs/1931159
commit a1149a6c06ee094a6e62886b0c0e8e66967a728a upstream.

Inserting an SD-card on an Intel NUC10i3FNK4 (which contains a GL9755)
results in the message:

    mmc0: 1.8V regulator output did not become stable

Following this message, some cards work (sometimes), but most cards fail
with EILSEQ. This behaviour is observed on Debian 10 running kernel
4.19.188, but also with 5.8.18 and 5.11.15.

The driver currently waits 5ms after switching on the 1.8V regulator for
it to become stable. Increasing this to 10ms gets rid of the warning
about stability, but most cards still fail. Increasing it to 20ms gets
some cards working (a 32GB Samsung micro SD works, a 128GB ADATA
doesn't). At 50ms, the ADATA works most of the time, and at 100ms both
cards work reliably.

Signed-off-by: Daniel Beer <dlbeer@gmail.com>
Acked-by: Ben Chuang <benchuanggli@gmail.com>
Fixes: e51df6ce668a ("mmc: host: sdhci-pci: Add Genesys Logic GL975x support")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210424081652.GA16047@nyquist.nev
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index fd76aa672e020445a2ee3777ab0cf623bb8b436c..4437ea4ec8596747337028dde6da032d2ce8d997 100644 (file)
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -318,8 +318,13 @@ static void sdhci_gli_voltage_switch(struct sdhci_host *host)
         *
         * Wait 5ms after set 1.8V signal enable in Host Control 2 register
         * to ensure 1.8V signal enable bit is set by GL9750/GL9755.
+        *
+        * ...however, the controller in the NUC10i3FNK4 (a 9755) requires
+        * slightly longer than 5ms before the control register reports that
+        * 1.8V is ready, and far longer still before the card will actually
+        * work reliably.
         */
-       usleep_range(5000, 5500);
+       usleep_range(100000, 110000);
 }
 
 static void sdhci_gl9750_reset(struct sdhci_host *host, u8 mask)