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Re: [Xen-devel] S3 resume issues

On Wed, Jan 16, 2013 at 6:09 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 16.01.13 at 12:05, Ben Guthro <ben@xxxxxxxxxx> wrote:
>> On Wed, Jan 16, 2013 at 5:57 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>>> And to me this
>>>>> would also imply that if you run without serial console, there
>>>>> wouldn't be an issue.
>>>> I thought this as well - but if I read the code correctly, it seems
>>>> that the ns16550 is set up for the legacy devices in
>>>> xen/arch/x86/setup.c _start_xen(), regardless of whether serial is
>>>> configured on the command line (if the hardware exists):
>>>>     /* We initialise the serial devices very early so we can get debugging.
>>>> */
>>>>     ns16550.io_base = 0x3f8;
>>>>     ns16550.irq     = 4;
>>>>     ns16550_init(0, &ns16550);
>>>>     ns16550.io_base = 0x2f8;
>>>>     ns16550.irq     = 3;
>>>>     ns16550_init(1, &ns16550);
>>> Yeah, but serial_resume() doesn't call their resume handlers
>>> unless their state is serial_initialized, which it can get to only
>>> through serial_parse_handle() seeing the right handle.
>> hmm, OK, I guess I missed that part.
>> I'll look closer today, to see if there is something in the config
>> space of this device that isn't getting preserved.
> Config space of a non-PCI device?

Your reply made me second-guess my assumption about the device - I
thought you meant to imply that it must be going through the PCI path
(perhaps I read too much into this)

I have been working under the assumption that the device at 0x3f8 is
not a PCI device, because of the io base... and never really verified
that it wasn't going through the PCI path. I suppose a PCI device
could provide that device, as well.

I'll have to look around for the Panther Point Chipset docs, to see if
it mentions anything about this.


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