Re: bmAttribute NO_REMOTE_WAKEUP
"Jon Smirl" <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On 3/17/07, Alan Stern <[email protected]> wrote: > On Sat, 17 Mar 2007, Jon Smirl wrote: > > > I just noticed that the PSC805 USB sound device has NO_REMOTE_WAKEUP > > set it it's configuration bits. Most of my other devices allow > > REMOTE_WAKEUP. > > > > Does this have anything to do with why the device won't come back from > > a suspend? > > No, or at least, not directly. They might both be symptoms of the same > design error. > > The REMOTE_WAKEUP attribute means that the device is capable of sending a > signal to the computer while it is suspended, asking to be resumed because > an event of some kind has occurred. It would be the appropriate way to > report that someone had pressed one of the switches while the device was > suspended, but apparently the PSC805 doesn't support it. > > > Two devices I have that also have NO_REMOTE_WAKEUP are both Wifi > > adapters. Wifi has it's own power saving scheme that allows it to poll > > for activity without being fully powered. > > What use is polling for activity if the devices have no way to report the > activity to the computer? I was wondering if this was a hint that the wifi devices aren't supposed to be suspended either. Most wifi devices have an embedded processor that would need to keep running. Wifi has a mode where it says: I'm going to shut down for xx ms and then wake up so if you have any traffic for me send it in the window where I'm awake. Wifi is pretty optimized for power savings since it is designed for battery operation. If you suspend the device I don't know if this wake in a window mode will keep working. > > Alan Stern > > -- Jon Smirl [email protected] ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel