| ubot5 | New news from planetubuntu: Stuart Langridge: Together in electric fags <http://www.kryogenix.org/days/2012/07/05/together-in-electric-fags> | 01:44 |
|---|---|---|
| jussi | electric fags :D Oh stuart, I love you :P | 05:52 |
| Tm_T | well that's a subject to discuss here (; | 06:09 |
| AlanBell | they are USB powered | 07:38 |
| AlanBell | wonder if they draw 100ma or negotiate for 500ma | 07:38 |
| AlanBell | dunno if they would need a kernel driver for that | 07:39 |
| ubot5 | New news from planetubuntu: James Henstridge: u1ftp: a demonstration of the Ubuntu One API <http://blogs.gnome.org/jamesh/2012/07/05/u1ftp/> | 09:46 |
| ubot5 | New news from planetubuntu: Luca Ferretti: GNOME 3.5.3 development release <http://blogs.gnome.org/lferrett/2012/07/05/gnome-3-5-3-development-release/> | 10:46 |
| ubot5 | New news from planetubuntu: Launchpad News: Meet Martin Packman in the Blue squad <http://blog.launchpad.net/meet-the-devs/meet-martin-packman-in-the-blue-squad> | 15:17 |
| m4v | AlanBell: The amount of current is determined by the type of load you connect. Lower imperance loads demand higher current. If they demand more than what the usb port can supply, the voltage drops and a short circuit follows if there's no build-in protection . | 20:26 |
| AlanBell | m4v: there is a negotiation protocol | 20:28 |
| m4v | there is? sounds silly to negotiate current for a constant voltage supply. | 20:28 |
| AlanBell | everything is allowed to draw 100ma at first which is one unit of load | 20:29 |
| AlanBell | they can ask the bus if they can have up to 5 units | 20:30 |
| AlanBell | this is so the voltage does not drop | 20:30 |
| AlanBell | it can just take 500ma, but that is outside the spec if it doesn't ask nicely for it | 20:31 |
| AlanBell | which is why some low quality netbooks crash when you plug in a 3G dongle | 20:31 |
| m4v | I see, there's a current limiter or protection circuit then. | 20:37 |
| AlanBell | I don't know how/if it is enforced | 20:37 |
| AlanBell | but to be within the spec a device has to ask nicely before taking lots of power | 20:37 |
| AlanBell | this means a completely dumb device can have 100ma and be a compliant USB device, but it has to have a tiny bit of cleverness to have a power negotiation conversation, but I am not sure if that means that aquarius's fags need a kernel driver | 20:41 |
| AlanBell | I would think that they would at least show up in lsusb if they are doing a power negotiation | 20:42 |
| m4v | might be at hardware level | 20:42 |
| m4v | is probably the current protection that is set to kick in at 100ma, and you negotiate for a higher limit. | 20:43 |
| m4v | but then... it shouldn't crash anything, the device would fail to work. | 20:44 |
| AlanBell | apparently they don't show up in lsusb | 20:46 |
| AlanBell | I have a hacked apart USB extension cable and a multimeter for checking current draw of USB devices, used it to prove that the netbook was crap, and the dongles were out of spec | 20:47 |
| m4v | power negotiation sounds like something that should be done at hardware level, but I'm just guessing. | 21:05 |
| === toddyhb is now known as toddy | ||
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