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SubjectRe: [PATCH 0/4] Fix forcedeth hibernate/wake-on-lan problems
Tobias Diedrich wrote:
> So my BIOS is not as borked as I thought and it should be possible
> to wake up the machine even with platform. Further debugging will
> have to wait until at least next weekend though (maybe longer)...

Or maybe it doesn't have to wait, I was just too curious:

Summary first: I got platform mode to work!

After grepping and reading through kernel/power/disk.c and
(rather obfuscated) drivers/acpi/.* code, and reading up on
ACPI _GPE (General Purpose Event?), and having a look at my DSDT I
noticed two things:

1) The network controllers are assigned to their own _GPE bits(pins?):
| Scope (\_GPE)
| {
| Method (_L0B, 0, NotSerialized)
| {
| Notify (\_SB.PCI0.MMAC, 0x02)
| }
| Method (_L0A, 0, NotSerialized)
| {
| Notify (\_SB.PCI0.MAC1, 0x02)
| }

2) drivers/acpi/sleep/proc.c registers a 'wakeup' file:
| proc_create("wakeup", S_IFREG | S_IRUGO | S_IWUSR,
| acpi_root_dir, &acpi_system_wakeup_device_fops);

And I then remembered that someone said in
it works for him if he writes $MAGICVALUE into a proc file.

And yes, if I write 'MMAC' and 'MAC1' into /proc/acpi/wakeup, then
wake-on-lan works even in platform mode.

AFAICS this bit of setup magic should not be required, because:

1) /proc/acpi/wakeup knows which pci device is associated to each GPE bit
|ranma@melchior:~$ cat /proc/acpi/wakeup
|Device S-state Status Sysfs node
|HUB0 S5 disabled pci:0000:00:06.0
|XVR0 S5 disabled
|XVR1 S5 disabled pci:0000:00:0e.0
|XVR2 S5 disabled
|XVR3 S5 disabled
|XVR4 S5 disabled
|XVR5 S5 disabled pci:0000:00:0a.0
|UAR1 S5 disabled pnp:00:09
|PS2K S4 disabled pnp:00:0b
|USB0 S4 disabled pci:0000:00:02.0
|USB2 S4 disabled pci:0000:00:02.1
|AZAD S5 disabled pci:0000:00:06.1
|MMAC S5 enabled pci:0000:00:08.0
|MAC1 S5 enabled pci:0000:00:09.0
(values after manually enabling MMAC and MAC1)

2) kernel/power/disk.c calls hibernation_ops->enter(), which is
acpi_suspend_enter, which calls acpi_enable_wakeup_device, which
sets up GPE wakup bits. This _should_ take care of enabling MMAC
and MAC1 automatically, but apparently does not work correctly at
some point.

I guess someone more knowledgable in ACPI stuff should have a look
at this.

Hope that helps,

Tobias PGP:
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