RE: [PATCH 1/1] AX88179_178A: Enable the hardware pseudo header in case of the NET_IP_ALIGN equals 0
From: Freddy Xin
On 2013年12月10日 09:01, David Miller wrote:
From: fre...@asix.com.tw
Date: Fri, 6 Dec 2013 17:58:18 +0800
From: Freddy Xin fre...@asix.com.tw
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 fre...@asix.com.tw
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?
You probably want to arrange to have save the appropriate offset in
one of the structures - so avoiding any conditionals during the allocate.
I've noticed that the RX URB are 20k bytes long.
Allocating that much physically and virtually contiguous memory for
every rx frame seems sub-optimal to say the least!
What does the skb's 'realsize' end up as?
I don't remember seeing a copy for short frames either.
ISTR there is code to debatch multiple ethernet frames from a single
URB. I think that means that an ethernet frame might end up in two URB.
I'm not sure there is code to handle that either - but I've not looked
that closely at that part of the code.
David
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Re: [PATCH 1/1] AX88179_178A: Enable the hardware pseudo header in case of the NET_IP_ALIGN equals 0
From: Freddy Xin fre...@asix.com.tw Date: Wed, 11 Dec 2013 14:17:59 +0800 I think there is no way of undoing the reservation in the driver. Then you should add a flag that, indeed, tells usbnet not to do the reservation in the first place. -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/1] AX88179_178A: Enable the hardware pseudo header in case of the NET_IP_ALIGN equals 0
On 2013年12月10日 09:01, David Miller wrote: From: fre...@asix.com.tw Date: Fri, 6 Dec 2013 17:58:18 +0800 From: Freddy Xin fre...@asix.com.tw 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 fre...@asix.com.tw 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? -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/1] AX88179_178A: Enable the hardware pseudo header in case of the NET_IP_ALIGN equals 0
From: fre...@asix.com.tw Date: Fri, 6 Dec 2013 17:58:18 +0800 From: Freddy Xin fre...@asix.com.tw 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 fre...@asix.com.tw 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. -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
