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Re: [Xen-devel] S3 resume issues

On 15/01/13 18:22, Ben Guthro wrote:
On Tue, Jan 15, 2013 at 1:17 PM, Malcolm Crossley
<malcolm.crossley@xxxxxxxxxx> wrote:
You get 0xFF when there is nothing responding to the ioport. If the 16550 is
on a PCI card then it could be the PCI connection has not been setup again
after the resume and you can't get to that ioport range.
This is not a PCI card, it is on onboard card (io base 0x3f8)

Interesting, it may be the serial device requires some ACPI method to be called to initialise/enable it correctly.

A serial port on a HP Elitebook 8570p we have seems to not initialise the serial port after the BIOS has started. The serial only starts working when the Linux kernel runs the ACPI enable method (halfway through the kernel boot) . I've tried to decompile the ACPI AML and it looks like it's enabling the serial via a microcontroller.

It could be you have a similar microcontroller based serial port on your system which can only be initialised via ACPI.

It might be worth checking that the io decode windows are enabled on the panther point chipset for the 0x3f8 port ranges. Check that bits 0-2 are 0 at address 0x80 and that bit 0 is 0 at address 0x82 in PCI device 0:1f config space.


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