Arch Linux

golwin

Member

From: Germany, Aachen

Registered: 2009-03-12

Posts: 35

[solved] ehci_hcd blocking uhci_hcd?

Is ehci_hcd (USB 2.0) maybe blocking uhci_hcd (USB 1.1)?

An ancient USB 1.1 hub died a few days ago and was replaces by a USB 2.0 hub. The scanner and keyboard/mouse are working fine, but the printer (Canon i560) isn't working properly anymore. It seems to be an USB 1.1 printer, so I tried

# modprobe -r ehci_hcd

and everything is working fine again. So far, so good.

Problem: I would like to keep USB 2.0 support. Is there a way to operate the printer with uhci_hcd, while ehci_hcd loaded? Or any other suggestions?

Last edited by golwin (2010-04-10 09:38:03)

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arch64 | awesome | screen | ranger | vim | cmus | weechat | bitlbee

ssri

Member

Registered: 2010-02-16

Posts: 216

Re: [solved] ehci_hcd blocking uhci_hcd?

could have something to do with the USB 2.0 scheduler not being enabled in the kernel
I had a problem with my cordless mouse using a usb 2 hub (2.6.32-11).

http://bbs.archlinux.org/viewtopic.php?id=91496

'Linux kernel 2.6.19 on i386.

CONFIG_USB_EHCI_TT_NEWSCHED:

This changes the periodic scheduling code to fill more of the low
and full speed bandwidth available from the Transaction Translator
(TT) in USB 2.0 hubs. Without this, only one transfer will be
issued in each microframe, significantly reducing the number of
periodic low/fullspeed transfers possible.

If you have multiple periodic low/fullspeed devices connected to a
highspeed USB hub which is connected to a highspeed USB Host
Controller, and some of those devices will not work correctly
(possibly due to "ENOSPC" or "-28" errors), say Y.

If unsure, say N.'

Last edited by ssri (2010-04-09 22:38:57)

golwin

Member

From: Germany, Aachen

Registered: 2009-03-12

Posts: 35

Re: [solved] ehci_hcd blocking uhci_hcd?

Thanks a lot! That's sounds very much like it.
But as I update frequently and don't need USB 2.0 urgently, I'm not really motivated to compile the kernel myself. So I guess I'll wait a bit to seen whether devs make it default
(btw: currently I'm running 2.6.33.2-1)

edit: marking as solved

Last edited by golwin (2010-04-10 09:39:46)

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arch64 | awesome | screen | ranger | vim | cmus | weechat | bitlbee

ssri

Member

Registered: 2010-02-16

Posts: 216

Re: [solved] ehci_hcd blocking uhci_hcd?

Thanks a lot! That's sounds very much like it.
But as I update frequently and don't need USB 2.0 urgently, I'm not really motivated to compile the kernel myself. So I guess I'll wait a bit to seen whether devs make it default
(btw: currently I'm running 2.6.33.2-1)

edit: marking as solved

Considering that vanilla kernels haven't had it enabled since 2.6.19 (three years ago), I wouldn't hold your breath.  Yeah, I understand not enabling a new scheduler when it first shows up on the scene, but I think three years would be enough time to sort out any issues that surrounded it initially.

ssri

Last edited by ssri (2010-04-10 18:33:57)