On Tue, 2010-10-19 at 22:47 +0200, Segher Boessenkool wrote:

It looks like it is the frame counter in an USB OHCI HCCA.
16-bit, 1kHz update, offset x'80 in a page.

So either the kernel forgot to call quiesce on it, or the firmware
doesn't implement that, or the firmware messed up some other way.

I vote for the FW being on crack. Wouldn't be the first time with
Pegasos.

It's an OHCI or an UHCI in there ?

Can you try in prom_init.c changing the prom_close_stdin() function to
also close "stdout" ? 

         if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
                 call_prom("close", 1, 0, val);
+        if (prom_getprop(_prom->chosen, "stdout", &val, sizeof(val)) > 0)
+               call_prom("close", 1, 0, val);

See if that makes a difference ?

Last option would be to manually turn the thing off with MMIO in yet-another
pegasos workaround in prom_init.c.

Cheers,
Ben.