Re: [PATCH v3 net] qede: fix firmware halt over suspend and resume

[John Meneghini <jmeneghi@redhat.com>]

Looks good.

Reviewed-by: John Meneghini <jmeneghi@redhat.com>

On 8/16/23 11:07, Manish Chopra wrote:
> While performing certain power-off sequences, PCI drivers are
> called to suspend and resume their underlying devices through
> PCI PM (power management) interface. However this NIC hardware
> does not support PCI PM suspend/resume operations so system wide
> suspend/resume leads to bad MFW (management firmware) state which
> causes various follow-up errors in driver when communicating with
> the device/firmware afterwards.
> 
> To fix this driver implements PCI PM suspend handler to indicate
> unsupported operation to the PCI subsystem explicitly, thus avoiding
> system to go into suspended/standby mode.
> 
> Without this fix device/firmware does not recover unless system
> is power cycled.
> 
> Fixes: 2950219d87b0 ("qede: Add basic network device support")
> Cc: David Miller <davem@davemloft.net>
> Signed-off-by: Manish Chopra <manishc@marvell.com>
> Signed-off-by: Alok Prasad <palok@marvell.com>
> ---
> V1->V2:
> * Replace SIMPLE_DEV_PM_OPS with DEFINE_SIMPLE_DEV_PM_OPS
> 
> V2->V3:
> * Removed unnecessary device NULL check in qede_suspend()
> * Updated the commit description to reflect that without
>    this fix firmware can't be recovered over suspend/resume
> ---
>   drivers/net/ethernet/qlogic/qede/qede_main.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
> index d57e52a97f85..c7911a13e8f5 100644
> --- a/drivers/net/ethernet/qlogic/qede/qede_main.c
> +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
> @@ -177,6 +177,15 @@ static int qede_sriov_configure(struct pci_dev *pdev, int num_vfs_param)
>   }
>   #endif
>   
> +static int __maybe_unused qede_suspend(struct device *dev)
> +{
> +	dev_info(dev, "Device does not support suspend operation\n");
> +
> +	return -EOPNOTSUPP;
> +}
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(qede_pm_ops, qede_suspend, NULL);
> +
>   static const struct pci_error_handlers qede_err_handler = {
>   	.error_detected = qede_io_error_detected,
>   };
> @@ -191,6 +200,7 @@ static struct pci_driver qede_pci_driver = {
>   	.sriov_configure = qede_sriov_configure,
>   #endif
>   	.err_handler = &qede_err_handler,
> +	.driver.pm = &qede_pm_ops,
>   };
>   
>   static struct qed_eth_cb_ops qede_ll_ops = {