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

[Shawn Lin]

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?

> Testing confirmed that the issue can be manually addressed by
> disabling runtime PM via sysfs:
> echo on > /sys/devices/platform/soc/2a310000.mmc/power/control
> 
> I experimented with various changes in the Device Tree, including
> lowering the bus frequency and attempting to keep the power domains
> active, but nothing stopped the retuning loop.
> The issue only went away when I forced the controller to stay active
> by disabling the runtime power management.
> 
> This quirk is the only way I have found to keep the SDR104 link from
> crashing on the NanoPi R76S, I am open to suggestions if there is
> a better way to handle this in the driver or the DTS.
> 
> Marco Schirrmeister (3):
>    dt-bindings: mmc: rockchip-dw-mshc: add rockchip,disable-runtime-pm
>    mmc: host: dw_mmc-rockchip: add rockchip,disable-runtime-pm quirk
>    arm64: dts: rockchip: add stability quirk to NanoPi R76S
> 
>   .../bindings/mmc/rockchip-dw-mshc.yaml        |  8 ++++++
>   .../boot/dts/rockchip/rk3576-nanopi-r76s.dts  |  1 +
>   drivers/mmc/host/dw_mmc-rockchip.c            | 25 ++++++++++++++++---
>   3 files changed, 31 insertions(+), 3 deletions(-)
>