在 2026/01/12 星期一 11:56, Shawn Lin 写道:

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

Except for the patch mentioned above for fixing the hot-plug problem
which you confirmed to work fine. I looked the code a bit and see
a potential problem related to the runtime suspend + power-domain.
Please check the patch to see if it fixes your problem:

--- a/drivers/mmc/host/dw_mmc-rockchip.c
+++ b/drivers/mmc/host/dw_mmc-rockchip.c

@@ -36,6 +36,8 @@ struct dw_mci_rockchip_priv_data {
         int                     default_sample_phase;
         int                     num_phases;
         bool                    internal_phase;
+       int                     sample_phase;
+       int                     drv_phase;
  };

  /*

@@ -573,9 +575,43 @@ static void dw_mci_rockchip_remove(struct 

platform_device *pdev)
         dw_mci_pltfm_remove(pdev);
  }

+static int dw_mci_rockchip_runtime_suspend(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct dw_mci *host = platform_get_drvdata(pdev);
+       struct dw_mci_rockchip_priv_data *priv = host->priv;
+
+       if (priv->internal_phase) {
+               priv->sample_phase = rockchip_mmc_get_phase(host, true);
+               priv->drv_phase = rockchip_mmc_get_phase(host, false);
+       }
+
+       return dw_mci_runtime_suspend(dev);
+}
+
+static int dw_mci_rockchip_runtime_resume(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct dw_mci *host = platform_get_drvdata(pdev);
+       struct dw_mci_rockchip_priv_data *priv = host->priv;
+       int ret;
+
+       ret = dw_mci_runtime_resume(dev);
+       if (ret)
+               return ret;
+
+       if (priv->internal_phase) {
+               rockchip_mmc_set_phase(host, true, priv->sample_phase);
+               rockchip_mmc_set_phase(host, false, priv->drv_phase);
+               mci_writel(host, MISC_CON, MEM_CLK_AUTOGATE_ENABLE);
+       }
+
+       return ret;
+}
+
  static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
         SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 
pm_runtime_force_resume)
-       RUNTIME_PM_OPS(dw_mci_runtime_suspend, dw_mci_runtime_resume, NULL)
+       RUNTIME_PM_OPS(dw_mci_rockchip_runtime_suspend, 
dw_mci_rockchip_runtime_resume, NULL)
  };

  static struct platform_driver dw_mci_rockchip_pltfm_driver = {

quoted

quoted

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(-)