Re: [PATCH v2 3/3] remoteproc: imx_dsp_rproc: Wait for suspend ACK only if WAIT_FW_CONFIRMATION is set

[Frank Li <Frank.li@nxp.com>]

On Thu, Dec 04, 2025 at 02:28:25PM +0200, Iuliana Prodan (OSS) wrote:
> From: Iuliana Prodan <iuliana.prodan@nxp.com>
>
> The DSP suspend path currently waits unconditionally for a suspend ack
> from the firmware. This breaks firmwares that do not implement the
> mailbox-based CONFIRMATION handshake, as the DSP never responds and
> system suspend fails with -EBUSY.
>
> The driver already uses the WAIT_FW_CONFIRMATION flag to indicate that
> the firmware supports the CONFIRMATION handshake at boot. Apply the same
> logic during suspend: only send the suspend message and wait for the
> suspend ack when the firmware is expected to support it.
>
> Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> Changes since v1:
> - Moved confirmation check earlier to avoid sending the message when
> FEATURE_SKIP_FW_CONFIRMATION is set, since RP_MBOX_SUSPEND_SYSTEM is
> not handled on the remote side.
> ---
>  drivers/remoteproc/imx_dsp_rproc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
> index 1f3a35756769..d03017d6b214 100644
> --- a/drivers/remoteproc/imx_dsp_rproc.c
> +++ b/drivers/remoteproc/imx_dsp_rproc.c
> @@ -1251,6 +1251,12 @@ static int imx_dsp_suspend(struct device *dev)
>  		goto out;
>  	}
>
> +	/* No fw confirmation expected, so trigger PM runtime suspend */
> +	if (!(priv->flags & WAIT_FW_CONFIRMATION)) {
> +		dev_dbg(dev, "No FW_CONFIRMATION needed, suspend directly.\n");
> +		goto out;
> +	}
> +
>  	reinit_completion(&priv->pm_comp);
>
>  	/* Tell DSP that suspend is happening */
> --
> 2.25.1
>