Re: [linux-pm] [PATCH v3 1/2] Input: enable i8042-level wakeup control

On Thu, 28 Jul 2011, Daniel Drake wrote:

On 28 July 2011 16:08, Alan Stern [off-list ref] wrote:

quoted

Aren't there? �I have no idea. �But if input devices are never
wakeup-capable, why do you name your function "input_may_wakeup()"?

I guess i8042_may_wakeup() would be a better name for it. In this
case, the only device in the hierarchy (i8042 -> serio -> input) that
is marked wakeup capable is the i8042 device (and only via my
patches). I'd welcome a better design.

My experience in this area is _extremely_ limited.  Take a look at
commits b14e033e17d0ea0ba (PNPACPI: Add support for remote wakeup) and 
3e6e15a862a0bc201 (Input: enable remote wakeup for PNP i8042 keyboard 
ports).

quoted

I'm using a normal PC with PS/2 mouse and keyboard. �It is set up with
the keyboard as a wakeup source but not the mouse. �Of course, this
uses ACPI, which I assume isn't present on OLPC.

It does depend on how the system is designed, yes. I suspect that the
device that is actually marked as wakeup capable on your setup is not
an input device, but rather another part of the /sys tree (perhaps
part of the ACPI tree?).

It is the PNP keyboard device (whichever that is!), enabled by the
second commit above.

Also, I suspect that if your system is woken
up by the keyboard, it loses the keypress which was used to wake it
up.

Could be; I don't recall ever having tested this.

I'm definitely open to better ways of doing this. The key considerations are:
1. We only have control over wakeups at the i8042 level; i.e. we
cannot ask for keyboard wakeups but not mouse.
2. Our keyboard and mouse hardware is guaranteed to be powered
throughout suspend
3. The key press or mouse movement or click that woke the system must
not be lost during resume. This means that all 3 layers (i8042, serio,
input) must not reset or really do anything with the device during
suspend/resume.

At this point I have reached my level of incompetence... so I'll shut 
up now.  :-)

Alan Stern

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