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Is it safe to turn off USB kickstart modules?

Posted: Sun Jan 29, 2012 11:04 am
by Raziel
Hi devs,

just for understanding...

I have an XE with a fixed USB/DMA hardware which is USB 1.1, right?
I don't have any USB2 cards, hubs or whatever.

OHCI is the old (1.0) standard?
UHCI is the new (1.1) standard?
EHCI is the enhanced (2.0) standard?

Is it possible/wise/sane to comment out EHCI(2.0) from kickstart or will this only bring grief later?

Just asking because i'm trying to find a way to use a Radeon HD card without the need to turn off USB completely
(USB and a HD card don't go well together, a plugged n card will crash the system as soon as USB is loaded in)

Thank you

Re: Is it safe to turn off USB kickstart modules?

Posted: Sun Jan 29, 2012 6:23 pm
by ZeroG
I have an XE with a fixed USB/DMA hardware which is USB 1.1, right?
yes.
OHCI is the old (1.0) standard?
UHCI is the new (1.1) standard?
EHCI is the enhanced (2.0) standard?
yes, yes and yes.
s it possible/wise/sane to comment out EHCI(2.0) from kickstart or will this only bring grief later?
It is possible to comment out ehci.usbhcd without any grief, just remember what you did if you install a USB2 card someday.

Re: Is it safe to turn off USB kickstart modules?

Posted: Sun Jan 29, 2012 7:21 pm
by Raziel
@ZeroG

Thanks for the answer, now for something i can't quite grab logically.

1) If i comment out OHCI and EHCI what would be the outcome?
I mean UHCI should, iiu logically, have backwards compatibility (OHCI) built in? Or did i twist my brain waves? :-)

Do USB1.0 cards/media/whatever even exist still?
Why not merge the xHCI into one?

2) What happens if i plug in an USB2 hub on the mainboard outlet?
Will it still be talked to with USB1.1 (mainboard?) or will EHCI kick in (because it's seen in USBInspectior as USB2.0 iirc)?

edit: added question 2 :-)

Re: Is it safe to turn off USB kickstart modules?

Posted: Mon Jan 30, 2012 6:26 pm
by ZeroG
@Raziel
1) If i comment out OHCI and EHCI what would be the outcome?
In that case you would be unable to use USB1.0 and USB2.0 devices.
I mean UHCI should, iiu logically, have backwards compatibility (OHCI) built in?
A usb device is passed down the driver chain (EHCI->UHCI->OHCI) until a matching driver is found.
2) What happens if i plug in an USB2 hub on the mainboard outlet?
Will it still be talked to with USB1.1 (mainboard?) or will EHCI kick in (because it's seen in USBInspectior as USB2.0 iirc)?
That depends on the USB2 hub hardware, it could have USB1.1 and / or USB 1.0 backward compatibility.
However: EHCI will not kick in because: a) you removed it from kickstart and b) your A1 has no EHCI hardware.

Re: Is it safe to turn off USB kickstart modules?

Posted: Mon Jan 30, 2012 8:17 pm
by Raziel
@ZeroG

kk, thanks a lot

Re: Is it safe to turn off USB kickstart modules?

Posted: Tue Jan 31, 2012 10:27 am
by Raziel
I cross-checked with Ranger (great utilitiy, should be part of the OS ;-) ) and it seems the OS is smart enough to only use those standards it can find hardware for.

In my case there is only UHCI listed in Exec/tasks and none else :-)

Happy :-D

Re: Is it safe to turn off USB kickstart modules?

Posted: Sat Feb 11, 2012 12:56 am
by Hypex
If you only have on board USB1.1 hardware there is no point removing EHCI as it won't be used.