On Fri, Feb 28, 2014 at 9:54 PM, Bakul Shah <ba...@bitblocks.com> wrote: > On Fri, 28 Feb 2014 09:45:42 EST Anthony Sorace <a...@9srv.net> wrote: >> >> Based on my own experience with USB weirdness with the Pi, I still suspec >> power issues. How are you powering the Pi itself? Using a 1 amp supply >> yielded >> problems, regardless of the sort of hub I had, which all went away when I >> switched to a 2 amp supply. I'm told the second generation of these boards >> are >> a bit better on that regard, but I don't have any to test. > > The RasPi FAQ suggest 1.2A or more. In rev 2 they replaced two > current limiting polyfuses with shunts so you can use a a > powered hub or connect periphs requiring > 100mA. > > The RasPi wastes a lot of power. Its processor require 1.8V > and only the USB requires 5V. For battery powered use people > have tried a number of tricks to reduce power use: replace the > onboard linear reg. with a switcher or two, tie 5V + 3.3V > together and only use a USB periphs that runs on 3.3V & use > model A Raspi -- the ethernet chip on model B draws a lot of > power even when idle and you don't need it for wifi. > Apparently Ralink RT5370 basedt cheapo wifi dongles can run on > 3.3V.
Okay, I tried a powered hub. Now, it boots with both keyboard and mouse (previously it used to hang when I connect both keyboard and mouse). But still the keyboard and mouse are not recognized. Once I saw a "warning" message that the descriptor length is short. But when I rebooted, I didn't see that message. Well, I now have a plan9 installation under qemu (compiled from the git sources, as I couldn't boot the one shipped with Debian unstable). If there is something I can try and test to help out with usb, I will gladly help. Thanks Ramakrishnan
