Re: [PATCH] net: qrtr: resend HELLO on MHI resume

[Thorsten Leemhuis]

On 9/9/26 07:58, Daniel J Blueman wrote:
> Since the MHI HELLO exchange was relocated, it is sent only at device
> registration. During a suspend-resume cycle, the firmware in WiFi
> cards such as WCN7850 indefinitely waits for another HELLO,
> triggering:
> 
>   ath12k_wifi7_pci 0004:01:00.0: timeout while waiting for restart complete
>   ath12k_wifi7_pci 0004:01:00.0: failed to resume core: -110
> 
> Fix this by triggering the handshake from resume_early in the MHI
> transport.
> 
> Validated on Qualcomm X1E-801800 on Lenovo Slim 7x across 10
> suspend-resume cycles.

For the record: Takashi ran into this regression as well and provided a
different fix, but withdrew it after I pointed out this fix, which
worked for Takashi. For details see:
https://lore.kernel.org/all/87mrtkpd2q.wl-tiwai@xxxxxxx/

Ciao, Thorsten
> Fixes: 544d85de4dc2 ("net: qrtr: Send HELLO message on endpoint register")
> Signed-off-by: Daniel J Blueman <daniel@xxxxxxxxx>
> ---
>  net/qrtr/af_qrtr.c | 13 +++++++++++++
>  net/qrtr/mhi.c     | 10 +++++++++-
>  net/qrtr/qrtr.h    |  2 ++
>  3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
> index 78347c937af7..2ffcfc2fdb4a 100644
> --- a/net/qrtr/af_qrtr.c
> +++ b/net/qrtr/af_qrtr.c
> @@ -623,6 +623,19 @@ static void qrtr_hello_work(struct work_struct *work)
>  	qrtr_port_put(ctrl);
>  }
>  
> +/* Trigger the HELLO handshake after the remote has been reset, eg on resume */
> +void qrtr_endpoint_hello(struct qrtr_endpoint *ep)
> +{
> +	struct qrtr_node *node = ep->node;
> +
> +	mutex_lock(&node->ep_lock);
> +	node->hello_sent = false;
> +	mutex_unlock(&node->ep_lock);
> +
> +	schedule_delayed_work(&node->say_hello, 0);
> +}
> +EXPORT_SYMBOL_GPL(qrtr_endpoint_hello);
> +
>  /**
>   * qrtr_endpoint_register() - register a new endpoint
>   * @ep: endpoint to register
> diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
> index 3990da1a65dc..50326ffa3401 100644
> --- a/net/qrtr/mhi.c
> +++ b/net/qrtr/mhi.c
> @@ -183,6 +183,7 @@ static int __maybe_unused qcom_mhi_qrtr_pm_suspend_late(struct device *dev)
>  static int __maybe_unused qcom_mhi_qrtr_pm_resume_early(struct device *dev)
>  {
>  	struct mhi_device *mhi_dev = container_of(dev, struct mhi_device, dev);
> +	struct qrtr_mhi_dev *qdev = dev_get_drvdata(dev);
>  	enum mhi_state state;
>  	int rc;
>  
> @@ -201,7 +201,13 @@ static int __maybe_unused qcom_mhi_qrtr_pm_resume_early(struct device *dev)
>  		return rc;
>  	}
>  
> -	return qcom_mhi_qrtr_queue_dl_buffers(mhi_dev);
> +	rc = qcom_mhi_qrtr_queue_dl_buffers(mhi_dev);
> +	if (rc)
> +		return rc;
> +
> +	qrtr_endpoint_hello(&qdev->ep);
> +
> +	return 0;
>  }
>  
>  static const struct dev_pm_ops qcom_mhi_qrtr_pm_ops = {
> diff --git a/net/qrtr/qrtr.h b/net/qrtr/qrtr.h
> index 3f2d28696062..de2de69a6199 100644
> --- a/net/qrtr/qrtr.h
> +++ b/net/qrtr/qrtr.h
> @@ -27,6 +27,8 @@ int qrtr_endpoint_register(struct qrtr_endpoint *ep, unsigned int nid);
>  
>  void qrtr_endpoint_unregister(struct qrtr_endpoint *ep);
>  
> +void qrtr_endpoint_hello(struct qrtr_endpoint *ep);
> +
>  int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len);
>  
>  int qrtr_ns_init(void);