From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kok, Auke" Subject: Re: [PATCH] fix e100 rx path on ARM (was [PATCH] e100 rx: or s and el bits) Date: Tue, 05 Jun 2007 16:33:12 -0700 Message-ID: <4665F2B8.3070805@intel.com> References: <4654B2E4.9010308@roinet.com> <039d8ee49a8dfcbff8695b19d0a1a5c4@bga.com> <465C4DBE.6000205@roinet.com> <94c8ff9069a77568513a9a1d1e60012d@bga.com> <4660856E.80403@roinet.com> <4665664D.30906@roinet.com> <46659CF7.2070003@intel.com> <20070605173904.GP31565@havoc.gtf.org> <4665A0B6.6020902@intel.com> <4112397f218a0744ebf8656c81acf850@bga.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org, Jesse Brandeburg , Milton Miller , Scott Feldman , John Ronciak , Jeff Kirsher , David Acker To: Jeff Garzik , Jeff Garzik Return-path: In-Reply-To: <4112397f218a0744ebf8656c81acf850@bga.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: e1000-devel-bounces@lists.sourceforge.net Errors-To: e1000-devel-bounces@lists.sourceforge.net List-Id: netdev.vger.kernel.org Milton Miller wrote: > On Jun 5, 2007, at 12:43 PM, Kok, Auke wrote: > >> Jeff Garzik wrote: >>> On Tue, Jun 05, 2007 at 10:27:19AM -0700, Kok, Auke wrote: >>>> We need to make sure that now that we're getting closer to 2.6.22 we >>>> don't end up killing e100 in it. Should we drop the current fixes in >>>> it to be on the safe side and aim for 2.6.23? I would hate to see an >>>> untested codepath breaking e100 on something like ppc or mips... >>>> that will be very painful >>> I certainly agree with this assessment... >>> I've been wondering if, based on all this recent work, we should >>> revert >>> the s-bit stuff and wait for 2.6.23. >> Yes, that's my point. If Milton and David agree I think we should do >> so immediately. > > We definitely need something other than what is in now. > > >> If so, do you want me to write a revert-patch or do you have some >> magic to do that for me? >> > > The simple git revert won't work because there have been other changes > (ioread for instance) that conflict. Hmm git-revert seems to do the job right. I checked it with git-show | patch -p1 -R and the results look OK. The two patches on top of the one we want to revert are unrelated enough to apply (manually it shows some fuzz, but otherwise it's OK). Jeff, please `git-revert d52df4a35af569071fda3f4eb08e47cc7023f094` to revert the following patch for now: --- commit d52df4a35af569071fda3f4eb08e47cc7023f094 Author: Scott Feldman Date: Wed Nov 9 02:18:52 2005 -0500 [netdrvr e100] experiment with doing RX in a similar manner to eepro100 I was going to say that eepro100's speedo_rx_link() does the same DMA abuse as e100, but then I noticed one little detail: eepro100 sets both EL (end of list) and S (suspend) bits in the RFD as it chains it to the RFD list. e100 was only setting the EL bit. Hmmm, that's interesting. That means that if HW reads a RFD with the S-bit set, it'll process that RFD and then suspend the receive unit. The receive unit will resume when SW clears the S-bit. There is no need for SW to restart the receive unit. Which means a lot of the receive unit state tracking code in the driver goes away. So here's a patch against 2.6.14. (Sorry for inlining it; the mailer I'm using now will mess with the word wrap). I can't test this on XScale (unless someone has an e100 module for Gumstix :) . It should be doing exactly what eepro100 does with RFDs. I don't believe this change will introduce a performance hit because the S-bit and EL-bit go hand-in-hand meaning if we're going to suspend because of the S- bit, we're on the last resource anyway, so we'll have to wait for SW to replenish. (cherry picked from 29e79da9495261119e3b2e4e7c72507348e75976 commit) --- Cheers, Auke ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/