14.07.2014 20:44, Jonas Gorski:
[...]
If I were to speculate wildly, I would guess that B44_RXMAXLEN refers to
the maximum frame length, not the maximum buffer length - and in the
code, it's being fed with the maximum buffer length.
This would allow the hardware to receive slightly oversized frames which
can corrupt the skb.
Since there is a public datasheet[1], this is easily verifiable, and
it looks you are right:
"Receive Maximum Length Register (RcvLength, Offset 0x404):
The value stored in this register specifies the largest valid Ethernet
Frame to be received."
Ok, so I'd suppose
bw32(bp, B44_RXMAXLEN, bp->dev->mtu + ETH_HLEN + 8 + RX_HEADER_LEN)
should instead be
bw32(bp, B44_RXMAXLEN, bp->dev->mtu + ETH_HLEN) ?
or
bw32(bp, B44_RXMAXLEN, bp->dev->mtu + ETH_HLEN + 8) ?
or maybe even
bw32(bp, B44_RXMAXLEN, bp->dev->mtu) ?
Apology for my ignorance, just can't stand testing it immediately to
hopefully get it right for BB.
Thank you.
Nikolai
The same is true for the XmtMaxLength register, which is also set "too
large" (it defaults to 1518).
Jonas
[1]: https://www.broadcom.com/collateral/pg/440X-PG02-R.pdf
.
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