On Mon, 26 Apr 2021 at 09:30, Ben Chuang [off-list ref] wrote:

Hi Daniel,

quoted

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.

Glad to receive your report. Thanks.

quoted

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.

If it is convenient, can you provide the appearance pictures and product
links of these two cards? We want to buy them.

quoted

Signed-off-by: Daniel Beer <redacted>
---
 drivers/mmc/host/sdhci-pci-gli.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 592d79082f58..061618aa247f 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c

@@ -627,8 +627,13 @@ 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);

Looks good for me.

I consider this as an ack and will add you tag to the commit. Please
tell me if I should change.

[...]

Applied for fixes and by adding the below tags, thanks!

Acked-by: Ben Chuang <redacted>
Fixes: e51df6ce668a ("mmc: host: sdhci-pci: Add Genesys Logic GL975x support")
Cc: stable@vger.kernel.org

Kind regards
Uffe