Subject: Re: [PATCH 2/6] net: davinci_emac: Fix runtime pm calls for davinci_emac

From: Felipe Balbi <[email-masked]>
Date: Tue, 13 Jan 2015 13:51:41 -0600

On Tue, Jan 13, 2015 at 11:29:24AM -0800, Tony Lindgren wrote:
> Commit 3ba97381343b ("net: ethernet: davinci_emac: add pm_runtime support")
> added support for runtime PM, but it causes issues on omap3 related devices
> that actually gate the clocks:
> 
> Unhandled fault: external abort on non-linefetch (0x1008)
> ...
> [<c04160f0>] (emac_dev_getnetstats) from [<c04d6a3c>] (dev_get_stats+0x78/0xc8)
> [<c04d6a3c>] (dev_get_stats) from [<c04e9ccc>] (rtnl_fill_ifinfo+0x3b8/0x938)
> [<c04e9ccc>] (rtnl_fill_ifinfo) from [<c04eade4>] (rtmsg_ifinfo+0x68/0xd8)
> [<c04eade4>] (rtmsg_ifinfo) from [<c04dd35c>] (register_netdevice+0x3a0/0x4ec)
> [<c04dd35c>] (register_netdevice) from [<c04dd4bc>] (register_netdev+0x14/0x24)
> [<c04dd4bc>] (register_netdev) from [<c041755c>] (davinci_emac_probe+0x408/0x5c8)
> [<c041755c>] (davinci_emac_probe) from [<c0396d78>] (platform_drv_probe+0x48/0xa4)
> 
> Let's fix it by moving the pm_runtime_get() call earlier, and also
> add it to the emac_dev_getnetstats(). Also note that we want to use
> pm_rutime_get_sync() as we don't want to have deferred_resume happen.
> 
> Cc: Brian Hutchinson <[email-masked]>
> Cc: Felipe Balbi <[email-masked]>
> Cc: Mark A. Greer <[email-masked]>
> Signed-off-by: Tony Lindgren <[email-masked]>
> ---
>  drivers/net/ethernet/ti/davinci_emac.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
> index 383ed52..deb43b3 100644
> --- a/drivers/net/ethernet/ti/davinci_emac.c
> +++ b/drivers/net/ethernet/ti/davinci_emac.c
> @@ -1538,7 +1538,7 @@ static int emac_dev_open(struct net_device *ndev)
>  	int i = 0;
>  	struct emac_priv *priv = netdev_priv(ndev);
>  
> -	pm_runtime_get(&priv->pdev->dev);
> +	pm_runtime_get_sync(&priv->pdev->dev);

gotta check return value on all pm_runtime_get_sync() calls. IIRC,
there's a coccinelle script for checking and patching this.

-- 
balbi