[PATCH] wireless: ath10k: Return early in ath10k_qmi_event_server_exit() to avoid hard crash on reboot

[Govind Singh]

Hi Kalle,

On 2020-08-28 18:22, Kalle Valo wrote:
> Amit Pundir <amit.pundir at linaro.org> writes:
> 
>> On Mon, 8 Jun 2020 at 17:07, Kalle Valo <kvalo at codeaurora.org> wrote:
>>> > I don't agree with this. If you read through the replies to the bug report,
>>> > it is clear that NS migration uncovered a corner case or even a bug. So we
>>> > should try to fix that indeed.
>>> 
>>> I'm with Mani, we should try to fix ath10k instead. Hopefully we can
>>> find a fix soon.
>> 
>> Hi Team,
>> 
>> Any updates on this? I can reproduce this hard crash on v5.9-rc1 as 
>> well.
>> 
>> It is not a blocker for us because we switched to a userspace
>> workaround, where we do not wait for modem to shutdown gracefully and
>> SIGKILL it instead, during the shutdown/reboot process. But I'm happy
>> to take a swing at any intermediate/in-progress solution available.
> 
> Govind submitted this patch and later he asked to drop it, but I think
> it would be a good idea to test it anyway:
> 
> ath10k: Move msa region map/unmap to init/deinit path
> 
> https://lkml.kernel.org/r/1591191231-31917-1-git-send-email-govinds@codeaurora.org
> 
> (patchwork is down so I cannot give a patchwork link)

This patchwork is not fixing the issue and changing MSA mapping sequence 
is major design change.
This issue is only seen with DB845 which uses SCM call, newer targets 
QCS404/SC7180/SM8150 will not have this issue as MSA mapping is 
hard-coded in TZ.
Probably changes in qmi layer to give different indication for this 
scenario and changes in FW is required to mitigate this issue 
gracefully.

BR,
Govind