Date: Thu, 6 May 2004 10:47:28 -0700 (PDT) From: Nate Lawson <nate@root.org> To: Mike Silbersack <silby@silby.com> Cc: acpi@freebsd.org Subject: Re: power savings and usb Message-ID: <20040506104654.E42462@root.org> In-Reply-To: <20040506113610.D2198@odysseus.silby.com> References: <200405052004.i45K4EnF029671@repoman.freebsd.org> <20040505171634.N37631@root.org> <20040506025051.V630@odysseus.silby.com> <20040506034307.M811@odysseus.silby.com> <20040506084132.L41848@root.org> <20040506113610.D2198@odysseus.silby.com>
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On Thu, 6 May 2004, Mike Silbersack wrote: > On Thu, 6 May 2004, Nate Lawson wrote: > > > > Gah, except that my experiment in clockswitching made the usb stack mad, > > > so it's constantly priniting "usb0: X scheduling overruns", where X > > > appears to be a number containing one or two bits of entropy per second. > > > I will have to go visit ohci.c with a cluebat when I get a chance. > > > > > > Er, it stopped when I plugged in the power cord, and starts again when I > > > unplugged it. Is it possible that ohci.c is reading some USB voltage > > > value instead of the overrun bit that it thinks it is reading? > > > > hw.acpi.cpu.cx_supported: C1/0 C2/84 C3/120 > > hw.acpi.cpu.cx_lowest: 1 > > hw.acpi.cpu.cx_history: 9175/0 173443/9175 0/0 > > > > This means I am requesting a lowest sleep of C2 (idx 1 of the options > > supported). The history values show that I haven't used C3 at all and am > > using C2 at a rate of about 95%. > > > > ohci may have problems with C3. On my uhci, it demotes to C2 without > > causing problems. You can override this by setting in /etc/rc.conf: > > > > economy_cx_lowest="1" > > > > -Nate > > Something else must be happening, because: > > hw.acpi.cpu.cx_supported: C1/1 C2/99 C3/288 > hw.acpi.cpu.cx_lowest: 0 > hw.acpi.cpu.cx_history: 5558639/0 0/0 0/0 > > But, since I went and killed the scheduling overrun interrupts at the > source, we don't need to worry anymore. :) Interesting. I'm not sure how the AC transition affected your USB then. -Nate
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