On Wed, Aug 7, 2013 at 1:09 AM, Grant Grundler <grundler@xxxxxxxxxx> wrote:
> On Tue, Aug 6, 2013 at 5:22 AM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> ...
>>> @@ -1310,6 +1318,10 @@ static int ax88179_reset(struct usbnet *dev)
>>>
>>> dev->net->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
>>> NETIF_F_RXCSUM;
>>> + if (dev->can_dma_sg) {
>>> + dev->net->features |= NETIF_F_SG | NETIF_F_TSO;
>>> + dev->net->hw_features |= NETIF_F_SG | NETIF_F_TSO;
>>> + }
>>>
>>
>> My concern with setting TSO on reset() is the following :
>>
>> Admin can disable TSO with
>>
>> ethtool -K ethX tso off
>>
>>
>> Then, one hour later, or one month later, a reset happens, and this code
>> magically re-enables TSO
>>
>> So, I really think this part should be removed from your patch.
>
> Following that logic, shouldn't all the features/hw_features settings
> be removed from reset code path?
This patch won't touch other settings because that isn't related with
this patch.
>
> hw_features shouldn't change since power up.
> FWIW, I do agree with you.
>
> I'll note that any "hiccup" in the USB side that causes the device to
> get dropped and re-probed will cause the same symptom. There is
I am afraid that PCI network devices' setting still won't survive unbound&
re-probed, will they?
> nothing the driver can do about it in this case. Perhaps add some udev
> rules to preserve ethtool settings the same way I've seen udev rules
> to record MAC address to enumerate devices (eth0, eth1, etc.)
Some usbnet devices may have random MAC address assigned in every
probe().
Thanks,
--
Ming Lei
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