Re: [PATCH] wifi: rtw89: retry efuse physical map dump on transient failure

[Christian Hewitt]

> On 2 Mar 2026, at 10:04 am, Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
> 
> Christian Hewitt <christianshewitt@xxxxxxxxx> wrote:
>>> On 2 Mar 2026, at 9:47 am, Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
>>> 
>>> Christian Hewitt <christianshewitt@xxxxxxxxx> wrote:
>>>> On Radxa Rock 5B with a RTL8852BE combo WiFi/BT card, the efuse
>>>> physical map dump intermittently fails with -EBUSY during probe.
>>>> The failure occurs in rtw89_dump_physical_efuse_map_ddv() where
>>>> read_poll_timeout_atomic() times out waiting for the B_AX_EF_RDY
>>>> bit after 1 second.
>>> 
>>> I'm checking internally how we handle this case.
>>> 
>>> [...]
>>> 
>>>> 
>>>> For context, firmware also fails (and recovers) sometimes:
>>> 
>>> Did you mean this doesn't always happen? sometimes?
>> 
>> It’s another intermittent behaviour observed on this board (and not
>> related to the issue this patch targets). It occurs less frequently
>> than the efuse issue and the existing retry mechanism in the driver
>> ensures firmware load always succeeds.
> 
> As intermittent behaviour, it might be not worth to try DMA. 
> 
> Recently, we have some patches related to PCI hardware settings. Please
> use the latest driver including patch [1] to see if it can be stable.
> 
> [1] af1e82232b98 ("wifi: rtw89: pci: restore LDO setting after device resume")

The efuse fail snippet that I posted alongside the patch was from a
Linux 7.0-rc1 kernel so that patch was already present.

>> We has seen similar log because of 36-bit DMA. Try below to force 32- or 36-
>>> bit DMA to see if it can resolve problem in your platform.
>> 
>> I can experiment but this doesn’t happen often so I probably can’t
>> provide meaningful feedback.