We are occationally seeing ethtool fail to communicate with ucc_geth.
I think I have tracked down why it happens, but I don't see a good way
to fix it.
When the phy state changes, adjust_link() checks if the state has changed
and if the link is up. If it is it does:
if (new_state) {
/*
* To change the MAC configuration we need to disable
* the controller. To do so, we have to either grab
* ugeth->lock, which is a bad idea since 'graceful
* stop' commands might take quite a while, or we can
* quiesce driver's activity.
*/
ugeth_quiesce(ugeth);
ugeth_disable(ugeth, COMM_DIR_RX_AND_TX);
out_be32(&ug_regs->maccfg2, tempval);
out_be32(&uf_regs->upsmr, upsmr);
ugeth_enable(ugeth, COMM_DIR_RX_AND_TX);
ugeth_activate(ugeth);
}
The problem I believe is that ugeth_quiesce() does netif_device_detach
which clears __LINK_STATE_PRESENT, and hence makes dev_ethtool fail
due to:
if (!dev || !netif_device_present(dev))
return -ENODEV;
So if ethtool happens to be run between ugeth_quiesce() and
ugeth_activate(), it fails as if the device simply doesn't exist, which
is of course not true, it's just temporarily disabled.
I don't see any obvious way to make the ethtool requests block while the
adjust_link does it's business. It seems that that making the device
disappear is the wrong thing to do though.
I am able to make it happen if I do:
'while ethtool ifname; do :; done' while plugging and unplugging the
cable for a few minutes.
Any suggestions?
--
len Sorensen
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