Re: USB device PM oddity in 3.5

[Josh Boyer <jwboyer@redhat.com>]

On Thu, May 24, 2012 at 04:48:26PM -0400, Alan Stern wrote:
> On Thu, 24 May 2012, Josh Boyer wrote:
> 
> > I'm testing Linus' tree as the merge window happens, and I've hit an
> > issue with what I believe is USB device power management (or something)
> > that is causing my mouse and keyboard to become unresponsive.  After a
> > very short time of non-use, either device will cut out.  I can move the
> > mouse around but it doesn't relay to the screen and I noticed this is
> > because the laser is turned off.  If I click a button on it, it will
> > turn back on and function again until a small period of non-use.  The
> > keyboard exhibits similar behavior, "ignoring" the first few key strokes
> > until it wakes back up.
> > 
> > I found this thread:
> > 
> > http://thread.gmane.org/gmane.linux.usb.general/64292
> > and
> > http://marc.info/?t=133552726500001&r=1&w=2
> > 
> > which have similar symptoms, but the kernels I'm using have the
> > subsequent patches applied.  I'm doing a git bisect at the moment, with
> > 72c04af as the starting good commit and 61011677 as the first bad.  I'll
> > let you know what comes of this, but I thought I'd mail about it now in
> > case anyone has any ideas.
> 
> It sounds like you have autosuspend enabled on the mouse and keyboard, 
> and they don't work very well with it.  Setting the sysfs power/control 
> attributes for the two devices to "on" will prevent autosuspend.
> 
> I don't know why this would have started happening after a kernel 
> upgrade.  Those settings are normally controlled by userspace apps.  
> Let us know what you find.

OK, the bisect turned up this as the first bad commit:

54d3f8c63d6940966217b807972778fb17c3fa82 is the first bad commit
commit 54d3f8c63d6940966217b807972778fb17c3fa82
Author: Matthew Garrett <mjg@redhat.com>
Date:   Fri May 11 16:08:28 2012 +0800

    usb: Set device removable state based on ACPI USB data
    
    ACPI offers two methods that allow us to infer whether or not a USB port
    is removable. The _PLD method gives us information on whether the port is
    "user visible" or not. If that's not present then we can fall back to the
    _UPC method which tells us whether or not a port is connectable.
    
    Signed-off-by: Matthew Garrett <mjg@redhat.com>
    Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

:040000 040000 d0845dc1e64bafbdc069d80edf1b43958e091b25 6cc92b4dd1f957d91572bbc60ebbff20e325d52f M	drivers

At this point I'm not really sure what I should be poking at to figure
out what/how the power is getting turned off to the keyboard and mouse.
I can provide acpidump output, etc.  Let me know what to check for and
I'll happily dig more.

josh