From mboxrd@z Thu Jan 1 00:00:00 1970 From: brian@walsh.ws (Brian Walsh) Date: Thu, 24 Sep 2009 19:43:20 -0400 Subject: ixp4xx dmabounce In-Reply-To: <19132.526.686296.154379@pilspetsen.it.uu.se> References: <19129.24807.954274.688709@pilspetsen.it.uu.se> <19131.41836.967832.872623@pilspetsen.it.uu.se> <19132.526.686296.154379@pilspetsen.it.uu.se> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Sep 24, 2009 at 7:34 PM, Mikael Pettersson wrote: > Brian Walsh wrote: >> > =C2=A0> I tried Krzysztof's patch and it had no noticeable affect. =C2=A0= >> I am still getting >> > =C2=A0> about 6.3 Mbps IP data throughput when only using the ohci contro= >> ller and >> > =C2=A0> about 3.6 Mbps when the device is attached to the ehci controller= >> . =C2=A0This >> > =C2=A0> device works fine when running the same testing attached to an x8= >> 6 >> > =C2=A0> configured machine and gets about 18 Mbps IP data throughput. >> > >> > If your application can operate in 64MB RAM, you may want to try >> > a kernel that includes only my ixp4xx disable dmabounce patch, >> > and boot it with mem=3D64M. (Look in the kernel boot log and verify >> > that it only sees 64M of RAM.) >> > >> > If performance increases, then your performance loss is due to bounces. >> > >> >> Mikael >> >> I used your patch to disable legacy bounce, disabled support for > 64MB RAM= >> , >> and used the mem=3D64M kernel option. ?There was no change in the data >> throughput. >> >> I am not sure where this leaves me. > > To me it implies that the performance issues are unrelated to > your initial bouncing issues. Since you get better performance > from OHCI I'd have to suspect a hardware or driver issue with > your EHCI controller. > Yes that is what I was thinking. I just tried 3 other PCI USB controller cards with different chipsets. All had the same results.