On Thursday 04 January 2007 12:27 am, Oliver Neukum wrote: > > I'll check tomorrow and see. Does HUB electronics include over-current > > sensing to detect that a device that says it wants 100ma is in fact > > attemping to draw 500ma ? > > No, protection is per hub, not port.
... on some hardware, yes it can be ganged. On other hardware, the reporting is per-port. The hub descriptor says which kind the hub uses. But there are wierd cases too, like when power switching is ganged but OC reporting isn't, and those cases aren't visible in the descriptors. That magic command thing is an ugly hack, and I've not seen such a thing before. Better would be to just have two different configurations. The "Blackberry runs out of power" issue might be improved by kicking in the autosuspend logic ... so the USB link could be in a low power state, and not suck so much power. (Notice I said "could"; maybe the device isn't that intelligent...) But of course that's not the same as being able to recharge the battery, either. If the question is whether a given hub port can provide 500 mA power, so that the driver should try to kick in the magic command sequence, right now I don't think there's a way to query usbcore about port power capabilities from drivers. - Dave ------------------------------------------------------------------------- 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 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
