Hi Shawn,

On 1/12/2026 11:56 AM, Shawn Lin wrote:

在 2026/01/12 星期一 9:32, Shawn Lin 写道:

quoted

在 2026/01/10 星期六 9:07, Marco Schirrmeister 写道:

quoted

This series addresses a microSD stability issue on the FriendlyElec
NanoPi R76S (RK3576). The board currently suffers from a 400kHz
retuning loop when the controller attempts to enter runtime-suspend
during idle periods.

Evidence of the failure in dmesg:
[Fri Jan  2 01:28:02 2026] mmc_host mmc1: Bus speed (slot 0) = 400000Hz
[Fri Jan  2 01:28:03 2026] mmc_host mmc1: Bus speed (slot 0) = 198000000Hz
[Fri Jan  2 01:28:03 2026] dwmmc_rockchip 2a310000.mmc: Successfully tuned phase to 233
[Fri Jan  2 01:28:04 2026] mmc_host mmc1: Bus speed (slot 0) = 400000Hz

Does this problem happen with all microSDs or just *a* microSD per
your description?
Have you ever tried to disable SDR104 support?

A quick update.

I found several problems on RK3576 for supporting sd cards. I wondered
how all upstream RK3576 boards claiming SD support work? Anyway, I sent
a series to the list[1], not sure if it fixes the problem you faced, but
these should be the right patches you should have a try.


[1]https://lore.kernel.org/linux-rockchip/1768189768-96333-1-git-send-email-shawn.lin@rock-chips.com/T/#t (local)

I encountered a similar issue on the RK3576 EVB2. 

It seems that the cd-gpios feature are broken, so SD card events
cannot be detected. However, if the SD card is inserted before Linux
boots, it can at least start up. I suspect that other boards may behave
the same way :)

-- 
Best, 
Chaoyi