Re: [PATCH] remoteproc: ti_k3_common: remove remote processor mailbox ping

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, Aug 06, 2025 at 02:48:17PM -0300, Hiago De Franco wrote:
> From: Hiago De Franco <hiago.franco@toradex.com>
> 
> As of today, pinging the remote processor during k3_rproc_request_mbox()
> does not have any functional effect. This behavior was originally based on
> the OMAP remoteproc driver, where the idea was to send messages such as
> suspend requests (among others) to the remote processor, but this was
> never upstreamed.
> 
> Currently, the ping message has no effect in upstream usage and causes an
> unread message to remain in the mailbox, which ultimately prevents the
> system from entering suspend mode:
> 
> Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
> printk: Suspending console(s) (use no_console_suspend to debug)
> omap-mailbox 29000000.mailbox: fifo 1 has unexpected unread messages
> omap-mailbox 29000000.mailbox: PM: dpm_run_callback(): platform_pm_suspend returns -16
> omap-mailbox 29000000.mailbox: PM: failed to suspend: error -16
> 
> The ping is only replied if the remote core firmware is capable of doing
> it, otherwise the unread message stays into the mailbox.
> 
> Remove the ping and fix the suspend issue.
> 
> Suggested-by: Andrew Davis <afd@ti.com>
> Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
> ---
> Hi,
> 
> this is the result patch of the discussion from
> 
> https://lore.kernel.org/lkml/20250725150713.barg5lhqr4reoxv3@hiagonb/
> ---
>  drivers/remoteproc/ti_k3_common.c | 15 ---------------
>  1 file changed, 15 deletions(-)
>

Applied - thanks,
Mathieu
 
> diff --git a/drivers/remoteproc/ti_k3_common.c b/drivers/remoteproc/ti_k3_common.c
> index d4f20900f33bdd92a59c62d0a7b166c4ad66ed16..8266e11914af87ac38977763099521dee4334348 100644
> --- a/drivers/remoteproc/ti_k3_common.c
> +++ b/drivers/remoteproc/ti_k3_common.c
> @@ -160,7 +160,6 @@ int k3_rproc_request_mbox(struct rproc *rproc)
>  	struct k3_rproc *kproc = rproc->priv;
>  	struct mbox_client *client = &kproc->client;
>  	struct device *dev = kproc->dev;
> -	int ret;
>  
>  	client->dev = dev;
>  	client->tx_done = NULL;
> @@ -173,20 +172,6 @@ int k3_rproc_request_mbox(struct rproc *rproc)
>  		return dev_err_probe(dev, PTR_ERR(kproc->mbox),
>  				     "mbox_request_channel failed\n");
>  
> -	/*
> -	 * Ping the remote processor, this is only for sanity-sake for now;
> -	 * there is no functional effect whatsoever.
> -	 *
> -	 * Note that the reply will _not_ arrive immediately: this message
> -	 * will wait in the mailbox fifo until the remote processor is booted.
> -	 */
> -	ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_ECHO_REQUEST);
> -	if (ret < 0) {
> -		dev_err(dev, "mbox_send_message failed (%pe)\n", ERR_PTR(ret));
> -		mbox_free_channel(kproc->mbox);
> -		return ret;
> -	}
> -
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(k3_rproc_request_mbox);
> 
> ---
> base-commit: 6bcdbd62bd56e6d7383f9e06d9d148935b3c9b73
> change-id: 20250805-v1-fix-am62-hmp-suspend-aed6a8de0225
> 
> Best regards,
> -- 
> Hiago De Franco <hiago.franco@toradex.com>
>