On 12/2/21 8:30 AM, Al Cooper wrote:
> The problem is in the .shutdown callback that was added to the
> sdhci-iproc and sdhci-brcmstb drivers to save power in S5. The
> shutdown callback will just call the sdhci_pltfm_suspend() function
> to suspend the lower level driver and then stop the sdhci system
> clock. The problem is that in some cases there can be a worker
> thread in the "system_freezable_wq" work queue that is scanning
> for a device every second. In normal system suspend, this queue
> is suspended before the driver suspend is called. In shutdown the
> queue is not suspended and the thread my run after we stop the
> sdhci clock in the shutdown callback which will cause the "clock
> never stabilised" error. The solution will be to have the shutdown
> callback cancel the worker thread before calling suspend (and
> stopping the sdhci clock).
> 
> NOTE: This is only happening on systems with the Legacy RPi SDIO
> core because that's the only controller that doesn't have the
> presence signal and needs to use a worker thread to do a 1 second
> poll loop.
> 
> Fixes: 5b191dcba719 ("mmc: sdhci-brcmstb: Fix mmc timeout errors on S5 suspend")
> Signed-off-by: Al Cooper <alcooperx@gmail.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian