Re: [PATCHv1] e1000e: Allow ethtool to enable/disable loopback.

On Wed, May 11, 2011 at 10:50 PM, Michał Mirosław [off-list ref] wrote:

W dniu 12 maja 2011 01:11 użytkownik Mahesh Bandewar
[off-list ref] napisał:

quoted

On Wed, May 11, 2011 at 12:15 PM, Michał Mirosław [off-list ref] wrote:

quoted

2011/5/11 Mahesh Bandewar [off-list ref]:

quoted

This patch adds e1000_set_features() to handle loopback mode. When loopback
is enabled, it enables internal-MAC loopback.

Please wait for this driver's conversion to hw_features. One comment
below, though.

This is not intrusive so should not create problems when that happens.

Fine by me then.

quoted

quoted

[...]

quoted

--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c

[...]

quoted

+static int e1000_set_features(struct net_device *dev, u32 features)
+{
+       u32 changed = dev->features ^ features;
+
+       if ((changed & NETIF_F_LOOPBACK) && netif_running(dev))
+               e1000_set_loopback(dev, features);
+
+       return 0;
+}

[...]

If e1000_set_loopback() fails, this should set dev->features to passed
features (but keeping NETIF_F_LOOPBACK unchanged in dev->features) to
keep the state consistent.

set_features() can return the return code of set_loopback() instead of
0; this way the consistency will be maintained.

Only as long as NETIF_F_LOOPBACK is the only bit set in hw_features.
netdev_update_features() can't really know which features were changed
and which failed when ndo_set_features callback returns non-zero.

This is more of an API shortcoming. Callback will have to revert
changes made (rollback) before returning non-zero value to keep it
consistent.

Thanks,
--mahesh..

Best Regards,
Michał Mirosław

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