Re: [PATCH 6.18.y] mailbox: Fix NULL message support in mbox_send_message()

[Sasha Levin]

On Thu, May 07, 2026 at 06:21:07AM +0000, Joonwon Kang wrote:
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index ff292b9e0be9..7a2baeca2ba4 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -361,7 +361,7 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>  	if (pchan->chan.rx_alloc)
>  		handle = write_response(pchan);
>
> -	if (chan->active_req) {
> +	if (chan->active_req != MBOX_NO_MSG) {
>  		pcc_header = chan->active_req;
>  		if (pcc_header->flags & PCC_CMD_COMPLETION_NOTIFY)
>  			mbox_chan_txdone(chan, 0);

This pcc.c hunk does not apply on 6.18.y: commit 5378bdf6a611 ("mailbox/pcc:
support mailbox management of the shared buffer") was reverted upstream by
f82c3e62b6b8, and that revert is already queued in 6.18 as 2cafad617431.
write_response() and the active_req-driven txdone path no longer exist in
pcc_mbox_irq() on 6.18, so this hunk is both syntactically inapplicable and
semantically unnecessary.

Could you send a v2 omitting the pcc.c hunk? The other three hunks
(mailbox.c, tegra-hsp.c, mailbox_controller.h) apply cleanly and I'm
happy to queue those for 6.18.y.

--
Thanks,
Sasha