Date: Sat, 11 Aug 2007 18:33:21 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: bruce@cran.org.uk Cc: current@FreeBSD.org Subject: Re: RE: Reboot on "shutdown -r" hangs after final "uptime ..." string Message-ID: <200708120133.l7C1XL54060302@gw.catspoiler.org> In-Reply-To: <20070812004103.GA20935@muon.bluestop.org>
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On 12 Aug, bruce@cran.org.uk wrote: > On Sun, Aug 12, 2007 at 01:22:51AM +0100, bruce@cran.org.uk wrote: >> By putting more printfs I see that it gets to the line "eec = >> pci_read_config" in ehci_pci_givecontroller and then appears to stop - >> I've got a printf at the end of ehci_pci_givecontroller that never gets >> displayed, and the printf at the top of the for loop only gets displayed >> once. >> > > After adding one more printf I see that it actually stops at the > pci_write_config line, not the pci_read_config. I wonder if the register write is triggering an SMI, which is sending the CPU off into the weeds. Take a look at sections 2.1.7 and 2.1.8 of the EHCI spec <http://developer.intel.com/technology/usb/download/ehci-r10.pdf>. You might want to print the values of eec and pci_read_config(self, eecp+4, 4) immediately before the call to pci_write_config(). Bit 13 of the latter will be the most interesting. Something that you might want to also print is the value of EOREAD4(sc, EHCI_USBSTS) immediately before the EOWRITE4(sc, EHCI_USBCMD, EHCI_CMD_HCRESET); call in ehci_hcreset(). Bit 12 of this register (EHCI_STS_HCH) should be a zero before the write to do the reset is performed. Maybe ehci_hcreset() needs to wait for that to happen (as is done in ehci_init()), rather than just waiting a fixed amount of time. I don't know much about SMI, but if the CPU is getting stuck in the SMI handler, then that might indicate that the problem is a BIOS bug.
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