[PATCH v1 0/3] mmc: dw_mmc-rockchip: Add stability quirk for NanoPi R76S

[Chaoyi Chen]

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

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