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

[Christian Hewitt]

> On 11 Mar 2026, at 7:05 am, Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
> 
> Christian Hewitt <christianshewitt@xxxxxxxxx> wrote:
>> 
>>> On 9 Mar 2026, at 6:35 am, Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
>>> 
>>> Christian Hewitt <christianshewitt@xxxxxxxxx> wrote:
>>>> 
>>>>> 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.
>>> 
>>> Sorry for the late.
>>> 
>>> We encountered WiFi/BT reading efuse at the same time causing similar
>>> problem as yours. The workaround is like yours, which adds timeout
>>> time.
>>> 
>>>>>>> 
>>>>>>> [...]
>>>>>>> 
>>>>>>>> 
>>>>>>>> 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.
>>> 
>>> This might be the same cause due to reading efuse in firmware.
>>> 
>>> Though we can add more timeout and retry times as workaround, I wonder
>>> if you can control loading time of WiFi and BT kernel modules?
>>> 
>>> More, can you do experiment that you load BT module first, and then load
>>> WiFi module after 10 seconds (choose a large number intentionally, or
>>> even larger)?
>> 
>> https://paste.libreelec.tv/charmed-turkey.sh
>> 
>> I’ve run the above script ^ which removes the wifi and bt modules in
>> sequence then reloads them in the reverse order with a delay between
>> bt and wifi modules loading, then checks for error messages. Over 200
>> test cycles with a 10s delay all were clean (no errors). I also ran
>> cycles with a 2 second delay and 0 second delay before starting wifi
>> module load and those were clear too. I guess that proves sequencing
>> avoids the efuse contention issue? - although it’s not possible in
>> the real-world so not sure there’s huge value in knowing that :)
> 
> Thanks for the experiments. 
> 
> Still want to know is it possible to change sequence/time of loading
> kernel modules at boot time from system level? I mean can you adjust
> the sequence in the Rock 5B board?

I’m not a kernel expert, but I’ve always understood module probe and
load ordering to not be guaranteed; as many things run in parallel and
are highly subjective to the specific hardware capabilities and kernel
config being used.

> In addition, did below messages not appear in these experiments? 
> 
> [    7.864148] rtw89_8852be 0002:21:00.0: fw security fail
> [    7.864154] rtw89_8852be 0002:21:00.0: download firmware fail

No, because even if we have a 0s delay between each group of modules
being loaded, they are loaded in series, so we workaround the issue.
Tweaking the script to background the module load loops so both run
in parallel would be closer to normal conditions, and I would expect
to start seeing failures and the retry mechanisms within the modules
(as added in this patch) being triggered.

Christian