more hints

[Kenneth Culver]

> If I remove "device pmtimer" from my config, I get a consistent panic,
> or variation of:
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address   = 0x0
> fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xc0135b0a7
> stack pointer           = 0x10:0xd68f2c48
> frame pointer           = 0x10:0xd68f2c64
> code  segment           = base 0x0 limit 0xffff, type 0x1b
> processor eflags        = interrupt enabled, resume, IOPL=0
> current process         = 12 (swi7: tty:sio clock)
> trap number             = 12
> panic page fault
>
> ...
>
>
> This is with leaving my USB 2.0 drive turned on during boot time.  If
> I use the same kernel (sans pmtimer) , but boot with my USB drive turned
> off, all is well.  Or, I can put pmtimer back in the kernel and boot
> with the drive turned on, but sooner or later I'll get some type of
> panic.  Some kind of timimg issue?.
>
> I think all of these panics have something to do with leaving the USB
> drive on at boot time.  It seems like I don't have any issues if it
> stays turned off.  That's probably why we're not seeing any reports, I
> doubt a lot of folks are using a USB 2.0 HD along with ehci...
>
> Again, all this started shortly after July 14th.  The USB DMA changes
> may have something to do with this...
>
I'll have time tomorrow to look at the commit logs, so I'll check out what
changes went in, then make patches for each one that is likely to be a
problem, and then submit them to you. That will allow you to pinpoint the
exact commit that caused the problem.

Ken