From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joakim Tjernlund Date: Mon, 23 Aug 2010 09:53:22 +0200 Subject: [U-Boot] [PATCH] UEC PHY: Speed up initial PHY neg. In-Reply-To: <4C721E61.5000608@gmail.com> References: <1281451009-26015-1-git-send-email-Joakim.Tjernlund@transmode.se> <4C721E61.5000608@gmail.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Ben Warren wrote on 2010/08/23 09:08:17: > > Hi Detlev, > > On 8/13/2010 1:20 AM, Detlev Zundel wrote: > > Hi Jocke, > > > >>>> Instead of always performing an autoneg, check if the PHY > >>>> already has a link and if it matches one of the requested > >>>> modes. Initially only 100MbFD is optimized this way. > >>> Isn't it about time that we think about _not_ stopping the ethernet > >>> device after every transaction? > >> Hi Detlev > >> > >> UEC does this already, my patch was to address the initial delay > >> you get for the first transaction. Now my PHY based boards gets the link > >> up just as quick as Fixed PHY for the first transaction. > > Forgive me to not look into this any deeper, but do I understand you > > correctly that you do this by essentially no-oping the eth_halt() > > function? Isn't this then effectively violating what net.c expects the > > device to do? > > > > I was thinking that net.c itself should not do this continous start/stop > > thing as it has problems on many interfaces. On one ARM machine I've > > again seen problems with the MAC address programming because the > > eth_halt() resets the controller and so it forgets its address again. > > Also the USB-CDC example where the _whole interface_ on the host side is > > being torn down after each tftp transfer prompts me to think along this > > line. > > > > So in effect I guess my response was rather a ping to Ben, sorry for > > that ;) > > > Sorry for the delay on this. I'm all for changing the existing > behavior. It seems to me that the only time we would ever want to wind > an interface down is if we switch the active one (even then, I'm not > sure). My world view is limited, but I can't imagine that even changing > interfaces happens much in real world U-boot usage, that is the non-lab, > non-interactive use cases. What would you think about adding something > like ifup and ifdown commands so that users could explicitly start/stop > interfaces? Sure, bringing I/F's up and down needlessly isn't a good thing. However my patch doesn't change that behaviour. It only optimizes the need for a PHY AN the first time one performs a eth transaction. Jocke > > Cheers > > Detlev > > > regards, > Ben > >