Re: [PATCH v2] mailbox: pcc: Fix command timeout due to missed interrupt

[Sudeep Holla]

On Thu, Jul 09, 2026 at 07:41:15PM +0800, Huisong Li wrote:
> PCC command execution can time out when a fast platform completes a
> transaction and signals the platform interrupt before pcc_send_data()
> marks the channel as in use. For shared platform interrupts, the type 3
> handler uses chan_in_use to decide whether the interrupt belongs to the
> channel. If it observes false, it ignores the completion and the caller
> waits until timeout.
> 
> Publish chan_in_use before ringing the doorbell. Use WRITE_ONCE() for
> the lockless flag update and READ_ONCE() in the interrupt handler when
> filtering shared interrupts. The following ordered MMIO accessor used for
> the doorbell keeps the earlier store visible before the platform is
> notified.
> 
> Clear chan_in_use with WRITE_ONCE() when completing the transaction,
> matching the lockless flag protocol used by the interrupt and send paths.
> 
> Fixes: 3db174e478cb ("mailbox: pcc: Support shared interrupt for multiple subspaces")
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxxxxx>
> Signed-off-by: Huisong Li <lihuisong@xxxxxxxxxx>
> Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxxxxx>

Sorry if I gave mixed feedback, you can't have both my signoff and reviewed-by
at the same time. You need to drop one of them.

-- 
Regards,
Sudeep