Re: [linux-usb-devel] [PATCH] USB: Only enable autosuspend by default on certain device classes

From: Adam Kropelin
Date: Fri Aug 03 2007 - 12:57:40 EST


Dave Jones wrote:
On Fri, Aug 03, 2007 at 05:31:52PM +0200, Jiri Kosina wrote:

Plus if you're connected to such a device for monitoring purposes
you're probably powered by it as well, so you have little to gain
from suspend even if it works.

I currently don't have any HID UPS by hand to verify, but I'd be
surprised if they would advertise remote wakeup capability ... ?

Looks like mine does..
[...]
idVendor 0x051d American Power Conversion
idProduct 0x0002 Back-UPS Pro 500/1000/1500

*notes to self to send pci.ids patch again*

bcdDevice 1.06
iManufacturer 3 APC
iProduct 1 Back-UPS ES 500 FW:801.e6.D USB FW:e6

Yup, I have one of those in my arsenal and see the same thing.

iSerial 2 AB0530291763
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup

I have reports of APC UPS remote wakeup working properly on "recent" PowerMac G5s running OS X, but was never able to duplicate that success on my cruddy old G3. I never figured out if it was a deficiency of the UPS, the G3, or the OS. So it is possible that with appropriate OS support this feature may actually work on certain UPSes (APC has a habit of messing up the firmware differently on each model, so it's likely hit-or-miss, but they are improving).

--Adam

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