Date: Tue, 22 Dec 2015 12:26:54 +0100 From: Bernd Walter <ticso@cicely7.cicely.de> To: Adrian Chadd <adrian@freebsd.org> Cc: Eugene Grosbein <eugen@grosbein.net>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: L2 cache management and busdma - or, "damnit USB, who you not like me" Message-ID: <20151222112653.GB21902@cicely7.cicely.de> In-Reply-To: <CAJ-VmomkmJy_P0-mDZA2TzS7viJ9GZH86sRZ5DAiV_eW6gFS0A@mail.gmail.com> References: <CAJ-Vmo=0E2%2B6=2JKROvw7i92qsrgoSnH0tDYSDLBk8s%2Bs6nEJQ@mail.gmail.com> <5678DAF8.6000807@grosbein.net> <CAJ-VmomkmJy_P0-mDZA2TzS7viJ9GZH86sRZ5DAiV_eW6gFS0A@mail.gmail.com>
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On Tue, Dec 22, 2015 at 12:12:55AM -0800, Adrian Chadd wrote: > hi, > > It shouldn't be - the atheros mips doesn't have l2 cache. > > I wish I could reproduce your issue. :( It is strange that you couldn't reproduce the problem. For me It happened on so many HW combinations of sticks and magnetic USB drive, with different AR9331 boards and also with the WDR-4300. On the other hand I know someone with a stable SATA-HDD on USB converter connected to a Carambola2, which is something I couldn't reproduce. Nevertheless, it is not a filesystem corruption thing. To me it is more suspect to corruption in USB controller request memory and not in the bulk payload. However, I have no evidence to proove this theory. > On 21 December 2015 at 21:09, Eugene Grosbein <eugen@grosbein.net> wrote: > > On 21.12.2015 12:02, Adrian Chadd wrote: > >> hi, > >> > >> I've been poking at the ci20 port to bring it up to > >> self-booting/running, and this involves using USB1 as a rootfs. Yeah, > >> I know, ohci, but that's what I have for now. > >> > >> Anyway, there was filesystem corruption, so I went digging into it and > >> found that we just weren't taking L2 cache line size into account when > >> doing the busdma bits. The JZ4780 SoC has 32 byte L1 lines, and 128 > >> byte L2 lines. Oops > >> > >> So, two things are needed: > >> > >> * for the ci20 port, which isn't in the mainline tree yet, we need to > >> use USB_HOST_ALIGN=128, and > >> * we need to teach the busdma code about the maximum line size, not > >> just the L1 line size. > >> > >> Here's a diff that does the latter: > >> > >> https://people.freebsd.org/~adrian/mips/mips-fix-dcache-busdma.diff > >> > >> I'm going to test this out on my L1-only platforms (read: atheros) tomorrow. > >> > >> Does anyone have any comments? > > > > Can that be the source of my USB problems? Total system hang while doing lots of umass I/O > > with TP-Link TL-WDR3600? If yes, I'd like to re-run my tests with these new patches. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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