[TriLUG] why does usb card on PCIe bus need extra power to detect a disk?

[Joseph Mack NA3T via TriLUG]

I have a machine with only a usb 2.0 hub. To get some usb 3.0 ports, I bought a 
PCIe card with two external USB 3.0 ports (Orico PVU3-201IV1).

The card comes with no instructions and no windows driver disk.

The card has a 10+10 pin, 0.1" spacing male connector with the last pin in one 
row missing. The shroud for the connector is keyed with a slot between pin 5-6. 
The slot is in a different place than for the ATX power supply key. Anyone know 
what this connector is for?

The card comes with a power cable:

o one end a Molex 4 pin connector that is standard for power for ATA drives

o other end is a (male) SATA power connector.

The card has the mating Molex 4 pin connector.

I had no idea why this cable came with the card, nor why the card had these two 
connectors. I decided to pretend they didn't exist.

The card is recognised by the Linux VIA driver (and the windows driver, which I 
found by searching), but when I plug in an external usb drive, the drive is not 
detected by the kernel (messages, debug, daemon) or by windows.

On looking around I find that the card does not work unless I plug in the power 
cable that comes with the card. I bought a sata power splitter cable from Intrex 
and powered up the card. Now plugging in an external disk works fine both with 
windows and Linux.

(there's a minor problem - the Molex connector on the card faces away from the 
mobo. When you plug in the cable, the connector on the cable runs into the 
computer case. Now I can't shut the lid. It would not have been difficult to 
orient the connector at 90deg to its current orientation.)

I'm wondering why this PCIe card is recognised by the kernel, but needs power 
for the external usb disk to be detected. The external disk has its own PS. I 
had assumed that only signal was going over the usb cable from the computer to 
the external disk. If some power is needed from the PCIe card for the external 
usb disk, why isn't the card getting it from the PCIe bus?

Also what is the 19 pin connector on the card?

Thanks Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant
map generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!