On Wednesday 10 June 2020 08:53:13 CEST Mohamed Dawod wrote:

Hello,

I read this point in staging/wfx/TODO file

- In wfx_cmd_send(), "async" allow to send command without waiting the reply. It may help in some situation, but it is not yet used. In add, it may cause some trouble: https://lore.kernel.org/driverdev-devel/alpine.DEB.2.21.1910041317381.2992@h... So, fix it (by replacing the mutex with a semaphore) or drop it.

I think that this issue has already been fixed in hif_shutdown() function, hasn't it ?

Indeed, when I wrote the TODO file, the function hif_shutdown() didn't exist yet.

I have another question. How can (replacing the mutex with a semaphore) solve the problem?

My understanding is that a mutex aims to be acquired and released from the same context. In some specific usages (RT-mutex? lock proving?), acquire mutex from a context and release it from another can produce some errors. In contrary a boolean semaphore does not have this restriction. (can anyone confirm that?) -- Jérôme Pouiller