From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] fix e100 rx path on ARM (was [PATCH] e100 rx: or s and el bits) Date: Fri, 15 Jun 2007 10:39:28 -0400 Message-ID: <4672A4A0.4070806@garzik.org> 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> <4665F2B8.3070805@intel.com> <46661B62.4070209@intel.com> <5d7f4c9757838906e0adf01d77632f35@bga.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "Kok, Auke" , e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org, Jesse Brandeburg , Scott Feldman , John Ronciak , Jeff Kirsher , David Acker , Jeff Garzik To: Milton Miller Return-path: In-Reply-To: <5d7f4c9757838906e0adf01d77632f35@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 6, 2007, at 4:28 AM, Milton Miller wrote: > >> >> On Jun 5, 2007, at 9:26 PM, Kok, Auke wrote: >> >>> Kok, Auke wrote: >>>>> >>>> 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) >>>> --- >>> >>> A little bit more is needed to explain why we're reverting it for >>> now. Jeff, please insert this into the revert commit. >>> >>> Auke >>> >>> -- >>> This patch attempted to fix e100 for non-cache coherent memory >>> architectures by using the cb style code that eepro100 had and using >>> the EL and s bits from the RFD list. Unfortunately the hardware >>> doesn't work exactly like this and therefore this patch actually >>> breaks e100 on those systems. >> >> on all systems. (Both the &| typo and the removed restart logic). >> >>> Reverting the change brings it back to the previously known good >>> state for 2.6.22. The pending rewrite in progress to this code can >>> then be safely merged later. >>> >>> Signed-off-by: Auke Kok >>> > > Jeff I don't see this in netdev upstream-fixes. Are you waiting on Auke > to respond to this? It should now be upstream, as of a day or two ago. Sorry for the delaying, was travelling, and wound up accidentally losing Auke's commit description. Jeff ------------------------------------------------------------------------- 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/