Re: sky2 PHY setup

[Stephen Hemminger <shemminger@linux-foundation.org>]

On Mon, 26 Mar 2007 21:24:06 -0600
Rob Sims <lkml-z@robsims.com> wrote:

> On Fri, Mar 16, 2007 at 02:16:48PM -0700, Stephen Hemminger wrote:
> > On Fri, 16 Mar 2007 14:36:45 -0600
> > Rob Sims <lkml-z@robsims.com> wrote:
> 
> > > Are there some debug hooks that can be activated?  My sky2 stops
> > > responding (very light load) about twice a day.  The netdev watchdog
> > > notices after a while and is able to reactivate the interface:
> 
> > > Mar 15 13:28:12 btd kernel: NETDEV WATCHDOG: eth0: transmit timed out
> > > Mar 15 13:28:12 btd kernel: sky2 eth0: tx timeout
> > > Mar 15 13:28:12 btd kernel: sky2 eth0: transmit ring 458 .. 435 report=458 done=458
> > > Mar 15 13:28:12 btd kernel: sky2 eth0: disabling interface
> > > Mar 15 13:28:12 btd kernel: sky2 eth0: enabling interface
> > > Mar 15 13:28:12 btd kernel: sky2 eth0: ram buffer 48K
> > > Mar 15 13:28:15 btd kernel: sky2 eth0: Link is up at 1000 Mbps, full duplex, flow control both
> > 
> > Use ethtool -S to if there are any pause frames, etc. See if frames are
> > still making it into PHY statistics but not being received.
> > 
> > Use ethtool -d to dump registers. Need current version of ethtool with decode logic.
> > 
> > Then look for things like is Ram buffer read/write pointer changing?
> > 
> > Is GMAC stuck in pause:
> > 
> > Normal is:
> > 	GMAC 1
> > 	Status                       0x5010  (see GM_GPSR_XXX in sky2.h)
> > 	Control                      0x1800
> > 
> > Stuck is
> > 	GMAC 1
> > 	Status			     0x5810 (or 0x5A10)
> 
> First, here's the described hang in action, on the Core2 Duo on a 1Gb
> hub:
> GMAC 1 Status/Control remains at 0x5010/0x1800 until module is removed.
> Read/write buffer pointers are changing.  Full ethtool output in
> http://www.robsims.com/sky2.netmon.log.gz
> 
> This machine was also having major throughput problems - 17 kB/s.
> Rebooting brought it to ~ 20 MB/s.  Booting into a kernel with the
> proprietary sk98lin kernel module showed ~ 80MB/s.  Finally, returning
> to sky2 gave 117 MB/s.  Tests run using netcat, dd, /dev/zero, and
> /dev/null, transmitting from the problem box to an e1000 via a Netgear
> GS108.  No hangs were observed during the "load test."

The vendor driver does not do hardware flow control correctly. It ignores
Tx pause frames.

Were you using Jumbo MTU?

> I also had a hang on a Pentium 4 w/sky2, 100Mb/s hub.  I neglected to
> try removing and re-inserting the module before rebooting.
> GMAC 1
> Status                       0xF004
This is [100mbit] [Full duplex] [Tx flow control disabled] [link up] 
	[Rx flow control disabled]

> Control                      0x1800
	[TX enabled] [Rx enabled]

You might have over run the hub and it wedged.  Try doing:
	ethtool -r eth0
that forces a down/up


-- 
Stephen Hemminger <shemminger@linux-foundation.org>