[PATCH] ARM64: dts: meson: disable sd-uhs modes on the libretech-cc

[PATCH] ARM64: dts: meson: disable sd-uhs modes on the libretech-cc

[Jerome Brunet]

There is a problem with the sd-uhs mode when doing a soft reboot.
Switching back from 1.8v to 3.3v messes with the card, which no longer
respond (timeout errors). According to the specification, we should
perform a card reset (power cycling the card) but this is something we
cannot control on this design.

Then the only solution to restore the communication with the card is an
"unplug-plug" which is not acceptable

Until we find a solution, if any, disable the sd-uhs modes on this design.
For the people using uhs at the moment, there will a performance drop as
a result.

Fixes: 3cde63ebc85c ("ARM64: dts: meson-gxl: libretech-cc: enable high speed modes")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
index 3e3eb31748a3..f63bceb88caa 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-libretech-cc.dts
@@ -234,9 +234,6 @@
 
 	bus-width = <4>;
 	cap-sd-highspeed;
-	sd-uhs-sdr12;
-	sd-uhs-sdr25;
-	sd-uhs-sdr50;
 	max-frequency = <100000000>;
 	disable-wp;
 
-- 
2.14.3

Re: [PATCH] ARM64: dts: meson: disable sd-uhs modes on the libretech-cc

[Kevin Hilman]

Jerome Brunet <jbrunet@baylibre.com> writes:

> There is a problem with the sd-uhs mode when doing a soft reboot.
> Switching back from 1.8v to 3.3v messes with the card, which no longer
> respond (timeout errors). According to the specification, we should
> perform a card reset (power cycling the card) but this is something we
> cannot control on this design.
>
> Then the only solution to restore the communication with the card is an
> "unplug-plug" which is not acceptable
>
> Until we find a solution, if any, disable the sd-uhs modes on this design.
> For the people using uhs at the moment, there will a performance drop as
> a result.
>
> Fixes: 3cde63ebc85c ("ARM64: dts: meson-gxl: libretech-cc: enable high speed modes")
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

Applied to v4.17/fixes, and adding a Cc to stable.

Thanks,

Kevin