[ipxe-devel] Regression on MCP77 for commit 947976da0

Robin Smidsrød robin at smidsrod.no
Sun Oct 28 21:34:54 UTC 2012


A recent commit introduced a regression on my MCP77-based LoM
(10de:0760). I did a git bisect and the commit below was identified as
the bad guy. The interesting part is that both my virtualbox and my
tg3-based laptop had no problems with this commit. I'm using ipxe.pxe
(i.e. native drivers) via chainloading.

947976da0caa929434775d978f2dcc7c9aee69f9 is the first bad commit
commit 947976da0caa929434775d978f2dcc7c9aee69f9
Author: Michael Brown <mcb30 at ipxe.org>
Date:   Wed Oct 24 13:26:51 2012 -0700

  [netdevice] Do not force a poll on net_tx()

  Including a netdev_poll() within net_tx() can cause the net_step()
  loop to end up processing hundreds or thousands of packets within a
  single step, since each received packet being processed may trigger a
  response which, in turn causes a poll for further received packets.

  Network devices must now ensure that the TX ring is at least as large
  as the RX ring, in order to avoid running out of TX descriptors.  This
  should not cause any problems; unlike the RX ring, there is no
  substantial memory cost incurred by increasing the TX ring size.

  Signed-off-by: Michael Brown <mcb30 at ipxe.org>

:040000 040000 bfbe3a595dd8a6b48dc7cf7ecf491b2d006cbbd1
1d52858ecb7b5ad6758ad64682264a3189e18821 M      src

-- Robin

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