Re: [PATCH] mailbox: Allow NULL message sending

[Jassi Brar]

On Tue, Nov 25, 2025 at 11:00 PM Joonwon Kang <joonwonkang@xxxxxxxxxx> wrote:
>
> Clients may want to send interrupt only without any useful message
> involved. Since the current mailbox framework does not allow NULL
> message sending(although it allows receiving it), the clients should
> allocate a dummy message buffer and pretend sending it. Besides, if
> the mailbox controller calls `mbox_chan_txdone()` when the client
> drivers happen to send NULL message anyway, it will result in unexpected
> results by making the tx status messed up. This commit lifts the
> limitation and allows the clients to send interrupt only without any
> message buffer allocated.
>
Interrupts without data messages are called 'doorbells' and we already
support them.
thanks