Messages in this thread | | | Date | Fri, 6 Jul 2012 16:37:15 -0700 (PDT) | From | Bill Unruh <> | Subject | Re: [Bug 43331] Re: Bug on bootup of Linux kernel on Panasonic Toughbook S10 |
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On Fri, 6 Jul 2012, Bjorn Helgaas wrote:
> On Sat, Jun 02, 2012 at 11:30:23AM +0800, Jiang Liu wrote: >> ... address range 0xfed98000-0xfed9ffff has been reserved by motherboard >> device(PNP0C02). I guess that BIOS has assigned address "0xfed98000" to >> 0000:00:04.0 for thermal management functionality. The BAR0 of >> 0000:00:04.0 may be locked down (can't be changed by OS) because the ACPI >> BIOS may have dependency on the assigned address ranges. > > I don't think the BAR can be completely read-only. If it were, we wouldn't > have any way to determine its size. We believe it is 32K in size: > > pci 0000:00:04.0: reg 10: [mem 0xfed98000-0xfed9ffff 64bit] > > so we should have written 0xffffffff to the low 32 bits of the BAR and read > back 0xffff8004 (32K = 2^15, so the low-order 15 bits should be read-only, > including the prefetchable bit (0), the type bits (10 for 64-bit), and the > memory space indicator (0)). > > Can you experiment with setting that BAR manually, e.g., by running these > commands as root: > > # setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 > # setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 > # setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1
planet:0[root]>setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 0006 fed98004 00000000 planet:0[root]>setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 planet:0[root]>setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1 fed98004 00000000 planet:0[root]
So it seems to work but does not change the base address (or was that what you meant by "does not work")
> > That's basically what the kernel does in pci_update_resource(), so this > will likely fail, too. > > In __pci_read_base(), where we size the BAR, we disable decoding first, > which we *don't* do in pci_update_resource(). So if the above doesn't > work, can you try this: > > # setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 > # setpci -s 00:04.0 COMMAND=0 > # setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 > # setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1
planet:0[root]>setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 0006 fed98004 00000000 planet:0[root]>setpci -s 00:04.0 COMMAND=0 planet:0[root]>setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 planet:0[root]>setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1 fed98004 00000000 planet:0[root]>
Ie, same thing-- no change in the address.
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