Re: [PATCH 1/2] remoteproc: imx_dsp_rproc: Skip RP_MBOX_SUSPEND_SYSTEM when mailbox TX channel is uninitialized

[Iuliana Prodan <iuliana.prodan@nxp.com>]

On 11/26/2025 10:14 PM, Bjorn Andersson wrote:
> On Tue, Nov 25, 2025 at 02:49:02PM +0200, Iuliana Prodan (OSS) wrote:
>> From: Iuliana Prodan <iuliana.prodan@nxp.com>
>>
>> Firmwares that do not use mailbox communication
>> (e.g., the hello_world sample) leave priv->tx_ch
>> as NULL. The current suspend logic unconditionally
>> sends RP_MBOX_SUSPEND_SYSTEM, which is invalid without
>> an initialized TX channel.
>>
>> Detect the no_mailboxes case early and skip sending
>> the suspend message. Instead, proceed directly to
>> the runtime PM suspend path, which is the correct
>> behavior for firmwares that cannot respond to mailbox
>> requests.
> 
> Please use the allotted 75 characters of width for your commit message.
> 
Right, will do in v2.

>>
>> Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
>> ---
>>   drivers/remoteproc/imx_dsp_rproc.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
>> index f11662f9a12f..fc0470aa72c1 100644
>> --- a/drivers/remoteproc/imx_dsp_rproc.c
>> +++ b/drivers/remoteproc/imx_dsp_rproc.c
>> @@ -1308,6 +1308,15 @@ static int imx_dsp_suspend(struct device *dev)
>>   	if (rproc->state != RPROC_RUNNING)
>>   		goto out;
>>   
>> +	/*
>> +	 * No channel available for sending messages;
>> +	 * indicates no mailboxes present, so trigger PM runtime suspend
>> +	 */
>> +	if (!priv->tx_ch) {
>> +		dev_err(dev, "No initialized mbox tx channel\n");
> 
> Commit message and comment above says this is "normal" behavior,
> dev_err() indicates that it's not. Should this be a dev_info()?
> 
> That said, it's still a message every time you suspend, so perhaps even
> omitting the print (or a dev_dbg()) makes more sense?
There's no error here; it's just a use case.
dev_dbg makes more sense, I agree.

> 
> Regards,
> Bjorn
> 
>> +		goto out;
>> +	}
>> +
>>   	reinit_completion(&priv->pm_comp);
>>   
>>   	/* Tell DSP that suspend is happening */
>> -- 
>> 2.34.1
>>