Trying to Disable USB 3, no luck

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jesmith
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Trying to Disable USB 3, no luck

Post#1 by jesmith » 04 May 2015, 19:11

I have found that on some hardware, booting Porteus from a USB 3 drive is not working very reliably, and so I'd like to be able to disable USB 3 support in the linux kernel. But I don't really want to have to rebuild the kernel to get there, if I can avoid it.

I've figured out where to put kernel command-line parameters, but I can't find a parameter that actually keeps the USB ports running at 2.0 speeds when you have a 3.0 drive in them.

I've tried:

modprobe.blacklist=xhci_hcd

and I've tried:

xhci_hcd.blacklist=yes

and in both cases confirmed they were there with 'cat /proc/cmdline' yet the xhci_hcd driver was loaded anyway, and lsusb -t confirms that the drives are running at full, flaky 3.0 speed.

Any suggestions?

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libernux
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Re: Trying to Disable USB 3, no luck

Post#2 by libernux » 04 May 2015, 19:49

Can you disable usb3 via the bios? It should continue to work but with usb2 speeds.
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donald
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Re: Trying to Disable USB 3, no luck

Post#3 by donald » 04 May 2015, 20:34

you can use a short USB 2 extension cable to connect the device.
This forces the USB 3 port to use USB 2 signalling.
A USB 3 device or cable has 9 pins, whereas a USB 2 device or cable only has 4 pins.
A USB 3 port will default to USB 2 signaling communication when only 4 pins are connected.
This way you wouldn't lose the ability to connect other USB 3 Devices to operate at full speed.

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