On Mon, Sep 29, 2025 at 02:26:01PM -0500, Tanmay Shah wrote: >> > > > >> > > > > + res = (chan->msg_count == (MBOX_TX_QUEUE_LEN - 1)); >> >> Please have a look at this condition again - the implementation of >> addr_to_rbuf() [1] is checking for space differently.
Tanmay, May I know why you want to compare with "MBOX_TX_QUEUE_LEN - 1", not "MBOX_TX_QUEUE_LEN"? >> >> [1]. >> https://elixir.bootlin.com/linux/v6.17/source/drivers/mailbox/mailbox.c#L32 >> >> > > > > + spin_unlock_irqrestore(&chan->lock, flags); >> > > > > + >> > > > > + return res; >> > > > > +} >> > > > > +EXPORT_SYMBOL_GPL(mbox_queue_full); >> > > > >> > > > add_to_rbuf is able to return ENOBUFS when call mbox_send_message. >> > > > Does checking mbox_send_message return value works for you? >> > > > >> > > >> > > That is the problem. mbox_send_message uses add_to_rbuf and fails. But >> > > during >> > > failure, it prints warning message: >> > > >> > > dev_err(chan->mbox->dev, "Try increasing MBOX_TX_QUEUE_LEN\n"); >> > > >> > > In some cases there are lot of such messages on terminal. Functionally >> > > nothing is wrong and everything is working but user keeps getting false >> > > positive warning about increasing mbox tx queue length. That is why we >> > > need >> > > API to check if mbox queue length is full or not before doing >> > > mbox_send_message. Not all clients need to use it, but some cane make >> > > use of >> > > it. >> > >> > I think check whether mbox_send_message returns -ENOBUFS or not should >> > work for you. If the "Try increasing MBOX_TX_QUEUE_LEN" message >> > bothers you, it could be update to dev_dbg per my understanding. >> > >> >> This new API is trying to avoid calling mbox_send_message(), no checking if >> it >> succeeded or not. I think it may not deserve to introduce a new API. add_to_rbuf is almost the first function that mbox_send_message calls. But if Tanmay insists on adding a new API, I am fine. Jassi may comment more. >> Moving dev_err() nto dev_dbg() is also the wrong approach. >> > >Correct. The caller of mbox_send_message detect error value and choose to add dev_err or not in caller driver, so I think dev_dbg is fine here. I would appreciate if there is explaination on why dev_dbg is not correct :) Thanks, Peng > >> > Regards, >> > Peng >> > >> > > >> > > >> > > > > + >> > > > > /** >> > > > > * mbox_send_message - For client to submit a message to be >> > > > > * sent to the remote. >> > > > >> > > > Regards >> > > > Peng >> > > >
