For my Arduino I get:
lsusb -vvv -d 0403:6001 | grep MaxPower
MaxPower 90mA
Obviously 260mA is way beyond 90mA. According to Wikipedia the default for an USB 2.0 device is 100mA, only high power devices may be allowed to draw 500mA.
What happens if you power USB through a stupid USB power supply instead of a hub?
WOW! You are good, answering my question before I even get to ask...
Makes perfect sense. I thought USB was always 500mA. I guess it would be up to the FTDI driver, so I wonder if there is a setting to request full power?
And here is my question before I got Server Error:
I'm having an issue with supplying power to my project, which includes the Arduino, GPS module, and 2x16 serial LCD from Modern Device.
Using just USB, the LCD is too dim to easily read and Arduino or GPS might become unstable. Measured voltage is 4.72V at the 5V pin.
Add external power supply set to 6V (measured 8.2V at Vin, 5V at 5V pin), everything works fine.
Run just off the external supply and the LCD flickers a bit at regular (~1/2 second) intervals, GPS does not enter Operate mode. Measured 8.2V at Vin and 5V at 5V pin. AC ripple is around 50mV, so I suspect there is some sort of transient that makes the LCD flicker and locks out GPS.
Set external supply to the 7.5V setting, measured 8.6V at Vin and 5V at the 5V pin, everything works, but Arduino's regulator gets hot, not burn your finger hot, but any hotter and it would be a struggle to keep a finger on it.
I measured the current out of the supply at this point and the total is less than ~260mA with all devices powered and running (spec for the GPS is typical ~200mA).
I don't understand why the USB cannot power the whole project or why the regulator gets hot when using the external supply set to 7.5V (8.6V actual)?
Power supply is a Radio Shack settable to 4.5, 6, 7.5, 9, 12V with an 800mA output rating.
You need to change the power descriptor in the FTDI EEPROM. Check the
FTDI IC datasheet.
I believe a lot of the USB ports will just deliver 500mA. You are fortunate enough
to have one that follows the spec 
(* jcl *)
A USB peripheral only gets 100mA by default, but it can negotiate with the hub for up to 500mA. IIRC, the spec says it must negotiate to get more than 100mA.
As someone already pointed out, you can use FTDI'S mprog to change the amount of current the USB chip requests.
-j
That's an idea, flash the FDTI chip?
Wonder why the Arduino board would not be preconfigured this way, given its intended use.
There are many uses of the Arduino. Since the range of experience of the users
is so broad limiting the current is a good design decision.
Having a TH uC is another good design decision.
(* jcl *)
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