From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: Date: Thu, 7 Apr 2005 23:12:54 -0400 From: jmk@plan9.bell-labs.com To: 9fans@cse.psu.edu Subject: Re: [9fans] etherigbe.c In-Reply-To: <830a180baf50d33ac3bf21dc23e6e710@coraid.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 35168d1c-ead0-11e9-9d60-3106f5b1d025 On Thu Apr 7 21:02:04 EDT 2005, brantley@coraid.com wrote: > ... > One question I have, though, is why do I want to touch the phy anyway? > Does anyone have a firm reason, other than the general `that's the way > we've always done it.' > ... we haven't always done it. in fact, we resisted for a very long time. the usual reason is that you don't know the state of either the mac or phy when you boot, so you reset both. sometimes the phy configures automatically, sometimes not. there are vendor specified registers in the phy which may need setting. there are bugs in the mac or phy which may need to be worked around. the phy and mac may be tightly coupled so the mac doesn't need any tweaking depending on what the phy does, or they may be more loosely coupled and changes in the phy configuratiuon (speed, duplex, pause) may require changes in the mac.