On Wednesday 29 August 2007 11:20:47 pm Russ Dill wrote:
> I have an AMD SB460 southbridge (has HPET), but a BIOS with no HPET
> support.
> ...
> I added this:
>
> Device (HPET)
> {
> Name (_HID, EisaId ("PNP0103"))
> Name (BUF0, ResourceTemplate ()
> {
> IRQNoFlags () {0}
> IRQNoFlags () {8}
> Memory32Fixed (ReadOnly, 0xFED00000, 0x00000400)
> })
>
> Method (_STA, 0, NotSerialized)
> {
> Return (0x0F)
> }
>
> Method (_CRS, 0, Serialized)
> {
> CreateDWordField (BUF0, 0x0A, HPT0)
> Store (0xFED01000, HPT0)
> Return (BUF0)
> }
> }
>
> ... I get the following message:
>
> hpet_acpi_add: no address or irqs in _CRS
>
> So, good news, drivers/char/hpet.c is finding my PNP0103 entry. Bad
> news, its having a problem with the resources. Any clue why?
If you look at drivers/char/hpet.c:hpet_resources(), you'll see that
it's fairly simple-minded. In particular, hpet_acpi_add() requires
both an address and an IRQ, but hpet_resources() only looks at
ACPI_RESOURCE_TYPE_EXTENDED_IRQ items.
I'm not an AML expert, but my guess is that your AML generates a
plain ACPI_RESOURCE_TYPE_IRQ, not an EXTENDED_IRQ item. If you can
write AML that generates an EXTENDED_IRQ item, I bet it will work.
This is a bug in the HPET driver. I think the right way to fix it
is to convert it from an ACPI driver to a PNP driver and let PNPACPI
do the resource parsing. That conversion is held up a bit right now
because PNP doesn't support enough IRQ descriptors for many HPETs,
but Thomas Renninger is working on the necessary PNP enhancements.
Bjorn
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