I forgot to mention that's not my case since even if I plug the two USB ends it still can't power up.
Best regards, Tiago On Sat, Apr 24, 2010 at 7:42 PM, Sameer Verma <[email protected]> wrote: > On Sat, Apr 24, 2010 at 4:55 PM, Tiago Marques <[email protected]> wrote: > > Hi all, > > I've ran into something on the 1.5 B2 I have here, which I'm in doubt if > may > > or may not be relevant for OLPC's hardware people(it seems not), so I'm > > reporting it anyway. > > All three USB ports can deliver enough power to an USB 2.5" HDD, no > problem. > > They cannot in the following conditions: > > - An extra SD card is plugged in > > - Another USB device is plugged in one port, even one of lower power > like a > > flash drive. (sometimes it only takes one, sometimes it takes two, SD > card > > power also seems to be an issue) > > When I try to plug in the 2.5" HDD, it doesn't have enough power to > spindle > > at enough speed and sits there trying to start itself. > > When plugging in an USB device or SD card after the 2.5" HDD is already > > working, it suffers a loss of power and enters the restarting state. This > is > > true if the SD card is plugged in instead(with another USB device > present), > > which suggests me that the power is shared. > > No other plugged devices seem to be rendered temporarily unaccessible due > to > > the power failure on the high power device. > > Best regards, > > Tiago > > _______________________________________________ > > Devel mailing list > > [email protected] > > http://lists.laptop.org/listinfo/devel > > > > I see a similar issue with a Lacie drive on my Dell desktop. This > drive actually comes with a cable that has two USB cables to draw > power from two ports. With two ports, the platter spins without any > problem. With one port, the disk clicks on the Dell. > > On a XO-1 G1G1, XO-1.5 B2 and XO-1.5 C2 I am able to power the same > drive via one port only both with a SD card and without a SD card. The > issue may very well be the USB drive power draw. I am using a LACIE > Design by FA Porsche http://bit.ly/9HD5uI > > This will be important for XS-on-XO scenarios, where we would > piggyback the /library partition onto an external drive. > > cheers, > Sameer > > -- > Dr. Sameer Verma, Ph.D. > Associate Professor, Information Systems > Director, Campus Business Solutions > San Francisco State University > http://verma.sfsu.edu/ > http://cbs.sfsu.edu/ > http://is.sfsu.edu/ >
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