Messages in this thread | | | Date | Thu, 28 Oct 2010 01:33:52 +0200 (CEST) | Subject | Re: Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, | From | "Segher Boessenkool" <> |
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>> 1) Figure out what exactly is going on; > > I thought we were past that.
We are not.
> The startup sequence leaves the device in a > bad > state (writing 1000 times per second to memory that the kernel believes is > not in use), so it needs to be given a reset command before the kernel > tries > to use that memory.
The question now is what causes the firmware to do that, and then what is the best way to stop it from doing that.
>> > The big question that I'm still stumbling over is how to access the >> device >> > registers. The "reg" property looks like this: >> >> You should look at "assigned-addresses", not "reg". Well, >> you first need to look at "reg" to figure out what entry >> in "assigned-addresses" to use.
Ignore this part, I was confused.
> The properties look like this: > > /pci@80000000/usb@5/assigned-addresses > 02002810 00000000 80000000 00000000 00001000
Lovely, incorrect data (it should start with 82002810, i.e., not relocatable -- it is already an assigned address!).
This means: 32-bit MMIO address space for bus 0 dev 5 fn 0, first BAR; assigned to address 80000000; size is 1000.
You could try a boot script like this:
dev /pci 0 ffff04 DO 0 i config-w! -100 +LOOP device-end
which should disable all PCI devices on all busses, on that PCI host bus (it disables every device behind pci-pci bridges separately, as long as every such bridge has a higher secondary bus number than primary bus number; if you only want to disable everything on the root bus (which should be sufficient), use ff04 instead of ffff04).
Segher
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