Thread (7 messages) flat view 7 messages, 4 authors, 2012-12-17

Re: Do I need to skb_put() Ethernet frames to a minimum of 60 bytes?

From: Ben Hutchings <hidden>
Date: 2012-08-14 20:36:00

On Tue, 2012-08-14 at 18:53 +0000, Arvid Brodin wrote:
Hi,

If I create an sk_buff with a payload of less than 28 bytes (ethheader + data),
and send it using the cadence/macb (Ethernet) driver, I get

eth0: TX underrun, resetting buffers

Now I know the minimum Ethernet frame size is 64 bytes (including the 4-byte
FCS), but whose responsibility is it to pad the frame to this size if necessary?
Mine or the driver's - i.e. should I just skb_put() to the minimum size or
should I report the underrun as a driver bug?
If the hardware doesn't pad frames automatically then it's the driver's
reponsibility to do so.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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