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Re: ohci vs ehci

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On Jan 21, 2008, at 19:14, Malcolm Herbert wrote:

I have a new Soekris net5501 with an internal 2.5in 250GB pata disk and the same model disk in an external USB2.0 enclosure. I'd like to create
a RAIDFrame mirror of the two but I suspect that ohci/ehci are getting
in the way and I'm ending up with a bus that's only running USB1.0

I first noticed this when raidctl claimed 4 days to sync the mirror,
which I thought a little excessive ... :)

I'm running NetBSD-4.0 GENERIC and the relevant portion of the boot
dmesg appears to be:

|ohci0 at pci0 dev 21 function 0: Advanced Micro Devices CS5536 OHCI USB Controller (rev. 0x02)
|ohci0: interrupting at irq 15
|ohci0: OHCI version 1.0, legacy support
|usb0 at ohci0: USB revision 1.0
|uhub0 at usb0
|uhub0: Advanced Micro OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
|uhub0: 4 ports with 4 removable, self powered
|ehci0 at pci0 dev 21 function 1: Advanced Micro Devices CS5536 EHCI USB Controller (rev. 0x02)
|ehci0: interrupting at irq 15
|ehci0: EHCI version 1.0
|ehci0: companion controller, 4 ports each: ohci0
|usb1 at ehci0: USB revision 2.0
|uhub1 at usb1
|uhub1: Advanced Micro Devices EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
|uhub1: 4 ports with 4 removable, self powered

To my mind, this indicates that the ohci driver is binding to the hardware
first and reducing the speed on the bus to USB1.0 speeds.

Nope, it doesn't. ohci handles low and full speed devices, high speed devices are handed over to ehci.

The question is, how can I remove ohci or reorder ohci and ehci so that I get better speed
out of the bus?

Have a look where your USB device attaches - if it's high speed it should got to uhub1, otherwise to uhub0.

have fun
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