Re: A desktop environment[1] kernel wishlist

[One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>]

On Tue, 05 May 2015 14:31:26 +0200

> For example, when you wake up from S3 on ACPI-based systems, the best you
> can get is what devices have generated the wakeup events, but there's
> no input available from that (like you won't know which key has been
> pressed).  You may not get that even.  You may only know what GPEs have
> caused the wakeup to happen and they may be shared.
> 
> For PCI wakeup, the wakeup event may be out of band.  You need to walk
> the hierarchy and check the PME status bits to identify the wakeup device
> and then you need to be careful enough not to reset it while putting into
> D0 for the input data associated with the event to be available.  I'm not
> sure how many device/driver combinations this actually works for.
> 
> For USB wakeup, you get the wakeup event from the controller which may be
> a PCI device.  Getting to the USB device itself from there requires some
> work and even then the device may not "remember" what exactly happened.
> 
> Further, if you wake up via the PC keyboard from suspend-to-idle, the
> wakeup key code is not available, the only thing you know is that the
> interrupts has occured (that may be changed, but it's how the current
> code works).

It's probably got to change, otherwise once machines get able to sleep
between keypresses it's going to suck every time you pause and think for
a minute then begin typing. Remember display being off for suspend is
purely a limitation of most current display panels.


Alan