Re: USB device PM oddity in 3.5

[Lan Tianyu <tianyu.lan@intel.com>]

On 2012/5/25 19:39, Josh Boyer wrote:
> 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.
hi josh:
	Have you cat power/runtime_status and control under usb device sys 
directory when the issue happen? We can determine which state the usb 
device is in when the issue is takeing place.

>
> josh


-- 
Best Regards
Tianyu Lan
linux kernel enabling team