Re: [PATCH] sh_eth: ensure pm_runtime cannot suspend the device during init

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Ben,

Thank you for the patch.

On Friday 14 March 2014 19:00:05 Ben Dooks wrote:
> It seems the pm_rumtime work queue is causing the device to be suspended
> during initialisation,

Have you investigated through which call path(s) this happens ? If device can 
be runtime suspended during their probe function despite calling 
pm_runtime_resume() then I don't see the point of that function at all.

> thus the initialisation may not be able to access registers properly. Use
> pm_runtime_get_sync() and pm_runtime_put_sync() to ensure that the pm system
> does not suspend it during the probe() call.
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> ---
>  drivers/net/ethernet/renesas/sh_eth.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/renesas/sh_eth.c
> b/drivers/net/ethernet/renesas/sh_eth.c index 4f76b5e..88aac2c 100644
> --- a/drivers/net/ethernet/renesas/sh_eth.c
> +++ b/drivers/net/ethernet/renesas/sh_eth.c
> @@ -2870,6 +2870,7 @@ static int sh_eth_drv_probe(struct platform_device
> *pdev) mdp->pdev = pdev;
>  	pm_runtime_enable(&pdev->dev);
>  	pm_runtime_resume(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);

I believe pm_runtime_resume() isn't needed anymore if we call 
pm_runtime_get_sync().

>  	if (pdev->dev.of_node)
>  		pd = sh_eth_parse_dt(&pdev->dev);
> @@ -2961,6 +2962,7 @@ static int sh_eth_drv_probe(struct platform_device
> *pdev) pr_info("Base address at 0x%x, %pM, IRQ %d.\n",
>  		(u32)ndev->base_addr, ndev->dev_addr, ndev->irq);
> 
> +	pm_runtime_put_sync(&pdev->dev);
>  	platform_set_drvdata(pdev, ndev);
> 
>  	return ret;

-- 
Regards,

Laurent Pinchart