How to wakup system from standby via USB keyboard

[Wu Zhangjin <wuzhangjin@gmail.com>]

Hi All,

After reading some documents in Documentation/ and the Internet, I found
there is an interface /proc/acpi/wakeup to set the wakeup devices on
machines support ACPI. but my machine does not support ACPI,
no /proc/acpi/wakeup there.

my machine is FuLoong2F, which is loongson based machine, it does not
support ACPI, but currently, I have made it support basic standby mode
for it has a 'wait' mode(after setting it's frequency to ZERO) and can
be waked up via an external interrupt. and here is the basic framework:

0. suspend:

arch_suspend_disable_irqs(disable all interrupts)

...

fuloong_pm_enter()

...

arch_suspend_enable_irqs(enable all interrupts)

1. fuloong_pm_enter:

setup_wakeup_interrupts()

loongson_pm_enter(put loongson into 'wait' mode)

3. setup_wakeup_interrupts

if the interrupt line is connected to loongson directly, no setup need
to do, but if there is an interrupt line connected to loongson
indirectly(i.e via i8259A), I need to get through the interrupt path via
enable(un-mask) the interrupts in interrupt controller and resuming the
devices earlier manually or enable the interrupt bit on the devices and
even or set a flag of the device driver to tell the system not suspend
this device.

I have tried the first(resuming earlier) and second method(enable the
interrupt bit) on the 8042 keyboard o YeeLoong(another loongson-based
machine, a netbook, i8042 is connected to i8259A directly), it works
well, but not tried the third method yet.

I guess the /proc/acpi/wakeup based method in user-space should be
something like this, but is there any relative method in kernel space?

there are only USB interfaces on FuLoong2F machines, I guess it will be
very hard to get through the interrupt path via the above two methods(I
have tried to enable the USB interrupt in south bright, but not work),
so, is there an easier method to do it?

Thanks & Regards,
Wu Zhangjin