On Mon, Sep 11, 2023 at 12:39:34PM -0700, Stephen Boyd wrote:
> It's possible for the completion in ipc_wait_for_interrupt() to timeout,
> simply because the interrupt was delayed in being processed. A timeout
> in itself is not an error. This driver should check the status register
> upon a timeout to ensure that scheduling or interrupt processing delays
> don't affect the outcome of the IPC return value.
>
> CPU0 SCU
> ---- ---
> ipc_wait_for_interrupt()
> wait_for_completion_timeout(&scu->cmd_complete)
> [TIMEOUT] status[IPC_STATUS_BUSY]=0
>
> Fix this problem by reading the status bit in all cases, regardless of
> the timeout. If the completion times out, we'll assume the problem was
> that the IPC_STATUS_BUSY bit was still set, but if the status bit is
> cleared in the meantime we know that we hit some scheduling delay and we
> should just check the error bit.
>
> Cc: Prashant Malani <[email protected]>
> Reviewed-by: Kuppuswamy Sathyanarayanan <[email protected]>
> Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Mika Westerberg <[email protected]>