Can not unload ath11k_pci and load it back

[Mark Herbert]

Found message in May archive of the mailing list with pretty similar 
issue that I have.

http://lists.infradead.org/pipermail/ath11k/2021-May/001267.html

The author of that message managed better debugging info than I did. It 
is same - if the kernel do autoloading of ath11k_pci  at boot it works. 
But  if I do manual load - it gets stuck in

"Wait for device to enter SBL or Mission mode"

sometimes instead of waiting it does report the versions of loaded 
firmware and the card works fine, but that happens very very rare. Once 
in 30-40 tries.

The message is produced by drivers/bus/mhi/core/boot.c file,  by

void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl) function.   
And this message seems to be generated if everything is working OK - so 
the card should reach this SBL or Mission mode and continue but it does 
not,  no follow up messages and the WiFi device is not available anymore.





On 07.10.2021 10:48, Kalle Valo wrote:
> Mark Herbert <mark.herbert42 at gmail.com> writes:
>
>> I've found similar bug files already - so not to create duplicates
>> simply commented there
>>
>> https://bugzilla.kernel.org/show_bug.cgi?id=214541
>>
>> Exactly - hibernation means saving state on disk and resuming later,
>> it is a very usefull feature when you are running out of battery and
>> want to save your work.
> Got it, thanks. So it seems we have two issues here: ath11k does not
> support hibernation and ath11k module reload failing. Let's handle the
> module reload failing in bug #214541, but can you file another bug about
> the missing support for hibernation? Let's have one issue per bug
> report, it's easier to manage bugzilla that way.
>
>> Also one more point I've found - if MHI is configured in the kernel -
>> the card is starting up on thr first boot and works. But if i
>> configure MHI as a module - it does not. MHI module do load. So do
>> ath11k and ath11k_pci.  But the last ath11k dmesg says :
>>
>> mhi mhi0: Wait for device to enter SBL or Mission mode
>>
>> Exactly as if I  do rmmod/modprobe sequence.
>>
>> I use latest BIOS from Dell (in fact upgrading 3.0.4 to 3.1.0 did not
>> cange anythng) ,  and have tried multiple kernels. Stable 5.14 series
>> and ath11k git tree (next and master-pending). Nothing helps.
>> Sometimes it woks out - I had couple of times successfully
>> rmmod/modprobe ath11k_pci but it s a kind of random and very rare
>> event ( I had it 2 times only).
>>
>> So for me it looks like an issue between MHI and ath11k , but
>> ubfortunately my knowledge is not enough to propose any solution here.
> On my NUC x86 test box I reload ath11k modules several times a day while
> I test ath11k but I always reload the mhi modules at the same time,
> maybe that makes the difference? Or XPS 13 9310 works differently from
> NUC, that's also possible.
>