* Re: ETHTOOL_GSET IOCTL on GigE links [not found] <46F9780F64AE9945815725F4C0C72CB803026226@hq-exch-1.corp.brocade.com> @ 2007-06-01 22:40 ` Jeff Garzik 2007-06-01 22:51 ` Jeff Haran 0 siblings, 1 reply; 5+ messages in thread From: Jeff Garzik @ 2007-06-01 22:40 UTC (permalink / raw) To: Jeff Haran; +Cc: linux-net, netdev Jeff Haran wrote: > With 10/100 Mbps links it wasn't such an issue since the devices tend to > support the same forced speeds and duplexities as they are capable of > negotiating, but with GigE links that's not always the case, at least > not according to what I've read. For instance, the following doc from > Sun http://www.sun.com/blueprints/0704/817-7526.pdf says that IEEE > 802.3ab says you can't force 1000Base-T over copper media (see page 4), > whereas some other physical media allow GigE to run without > autonegotiation (there's apparently this "serdes" interface that allows > it, for instance). > > Seems like there should be another field named something like > supported_forced to indicate what can be forced on the interface. Either > that or some more SUPPORTED_* bits to indicate supported forced modes. The 'supported' field has nothing at all to do with auto-negotiation. The driver should list all possibilities in that field, even if some are ONLY supported via 'forced' selection. Jeff P.S. netdev@linux.kernel.org is a far more active list, and is where the network stack/driver developers appear. ^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: ETHTOOL_GSET IOCTL on GigE links 2007-06-01 22:40 ` ETHTOOL_GSET IOCTL on GigE links Jeff Garzik @ 2007-06-01 22:51 ` Jeff Haran 2007-06-01 22:59 ` David Miller 2007-06-01 23:04 ` Jeff Garzik 0 siblings, 2 replies; 5+ messages in thread From: Jeff Haran @ 2007-06-01 22:51 UTC (permalink / raw) To: Jeff Garzik; +Cc: linux-net, netdev > -----Original Message----- > From: Jeff Garzik [mailto:jeff@garzik.org] > Sent: Friday, June 01, 2007 3:40 PM > To: Jeff Haran > Cc: linux-net@vger.kernel.org; netdev > Subject: Re: ETHTOOL_GSET IOCTL on GigE links > > Jeff Haran wrote: > > With 10/100 Mbps links it wasn't such an issue since the > devices tend to > > support the same forced speeds and duplexities as they are > capable of > > negotiating, but with GigE links that's not always the > case, at least > > not according to what I've read. For instance, the > following doc from > > Sun http://www.sun.com/blueprints/0704/817-7526.pdf says that IEEE > > 802.3ab says you can't force 1000Base-T over copper media > (see page 4), > > whereas some other physical media allow GigE to run without > > autonegotiation (there's apparently this "serdes" interface > that allows > > it, for instance). > > > > Seems like there should be another field named something like > > supported_forced to indicate what can be forced on the > interface. Either > > that or some more SUPPORTED_* bits to indicate supported > forced modes. > > > The 'supported' field has nothing at all to do with auto-negotiation. > > The driver should list all possibilities in that field, even > if some are > ONLY supported via 'forced' selection. > > Jeff > OK, but my question remains. In the case where a device supports one set of speeds via autonegotiation and another set via forcing, how does one tell which speeds can be forced and which can be autonegotiated? Thanks, Jeff Haran ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ETHTOOL_GSET IOCTL on GigE links 2007-06-01 22:51 ` Jeff Haran @ 2007-06-01 22:59 ` David Miller 2007-06-01 23:04 ` Jeff Garzik 1 sibling, 0 replies; 5+ messages in thread From: David Miller @ 2007-06-01 22:59 UTC (permalink / raw) To: jharan; +Cc: jeff, linux-net, netdev From: "Jeff Haran" <jharan@Brocade.COM> Date: Fri, 1 Jun 2007 15:51:18 -0700 > OK, but my question remains. In the case where a device supports one set > of speeds via autonegotiation and another set via forcing, how does one > tell which speeds can be forced and which can be autonegotiated? Unfortunately, as you have noted, this information is not given at the moment. I got bit by this the other week when I wanted to try forcing gigabit on a tg3 and the driver wouldn't allow it because it only allows forcing link speeds at 10/100 on copper links. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ETHTOOL_GSET IOCTL on GigE links 2007-06-01 22:51 ` Jeff Haran 2007-06-01 22:59 ` David Miller @ 2007-06-01 23:04 ` Jeff Garzik 2007-06-01 23:09 ` Jeff Haran 1 sibling, 1 reply; 5+ messages in thread From: Jeff Garzik @ 2007-06-01 23:04 UTC (permalink / raw) To: Jeff Haran; +Cc: linux-net, netdev Jeff Haran wrote: > OK, but my question remains. In the case where a device supports one set > of speeds via autonegotiation and another set via forcing, how does one > tell which speeds can be forced and which can be autonegotiated? The interface does not currently support such enumeration. You can certainly attempt forcing a speed, and see what happens. The driver will either (a) work, (b) refuse and give you an error message, or (c) present you with a situation that requires filing a driver bug report :) Jeff ^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: ETHTOOL_GSET IOCTL on GigE links 2007-06-01 23:04 ` Jeff Garzik @ 2007-06-01 23:09 ` Jeff Haran 0 siblings, 0 replies; 5+ messages in thread From: Jeff Haran @ 2007-06-01 23:09 UTC (permalink / raw) To: Jeff Garzik; +Cc: linux-net, netdev > -----Original Message----- > From: Jeff Garzik [mailto:jeff@garzik.org] > Sent: Friday, June 01, 2007 4:05 PM > To: Jeff Haran > Cc: linux-net@vger.kernel.org; netdev > Subject: Re: ETHTOOL_GSET IOCTL on GigE links > > Jeff Haran wrote: > > OK, but my question remains. In the case where a device > supports one set > > of speeds via autonegotiation and another set via forcing, > how does one > > tell which speeds can be forced and which can be autonegotiated? > > The interface does not currently support such enumeration. > > You can certainly attempt forcing a speed, and see what happens. The > driver will either (a) work, (b) refuse and give you an error > message, > or (c) present you with a situation that requires filing a driver bug > report :) > > Jeff Are there any plans in the works to modify the interface to provide this information? Thanks, Jeff Haran ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2007-06-01 23:09 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <46F9780F64AE9945815725F4C0C72CB803026226@hq-exch-1.corp.brocade.com>
2007-06-01 22:40 ` ETHTOOL_GSET IOCTL on GigE links Jeff Garzik
2007-06-01 22:51 ` Jeff Haran
2007-06-01 22:59 ` David Miller
2007-06-01 23:04 ` Jeff Garzik
2007-06-01 23:09 ` Jeff Haran
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).