Re: [PATCH 1/1] AX88179_178A: Enable the hardware pseudo header incase of the NET_IP_ALIGN equals 0

From: Freddy Xin
Date: Wed Dec 11 2013 - 01:23:21 EST



On 2013å12æ10æ 09:01, David Miller wrote:
From: freddy@xxxxxxxxxxx
Date: Fri, 6 Dec 2013 17:58:18 +0800

From: Freddy Xin <freddy@xxxxxxxxxxx>

The AX88179_178A has a hardware feature that it can insert a 2-bytes pseudo
header in front of each received frame by setting the AX_RX_CTL_IPE bit.
This feature is used to let the IP header be aligned on a doubleword-aligned address,
but the NET_IP_ALIGN may equals to 2 and the __netdev_alloc_skb_ip_align in USBNET will
reserve 2 bytes also, so in this case the driver shouldn't enable this bit.

This patch modifies the driver to set AX_RX_CTL_IPE just in case of the NET_IP_ALIGN equals 0.

Signed-off-by: Freddy Xin <freddy@xxxxxxxxxxx>
Please avoid larger than 80 column lines in your commit messages,
people use text-only tools to viee these.

Next, it makes no sense to restrict your change to NET_IP_ALIGN==0

Simply handle any case, by undoing the reservation if it's getting
in the way. If there isn't an appropriate helper for this, add one.

I think there is no way of undoing the reservation in the driver.
Can I add a flag of the driver_info, and use it to determine
whether undoing the reservation in rx_submit of usbnet?
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