Arch Linux

eilenbeb

Member

Registered: 2009-03-08

Posts: 44

[solved, false advertising]USB 2.0 device showing up as USB 1.0 device

First of all, here's the relevant portion of lspci:

00:02.0 USB controller: nVidia Corporation MCP78S [GeForce 8200] OHCI USB 1.1 Controller (rev a1)
00:02.1 USB controller: nVidia Corporation MCP78S [GeForce 8200] EHCI USB 2.0 Controller (rev a1)
00:04.0 USB controller: nVidia Corporation MCP78S [GeForce 8200] OHCI USB 1.1 Controller (rev a1)
00:04.1 USB controller: nVidia Corporation MCP78S [GeForce 8200] EHCI USB 2.0 Controller (rev a1)

...and my lsusb...

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 002: ID 0d8c:013c C-Media Electronics, Inc.

(Yes, I decided to try a USB sound card.)  As you can see, it's connecting to one of the 1.1 root hubs.
It doesn't matter which USB port I use, it always hooks up on bus 3 or 4.
I tried another USB 2.0 device on this system, and it always hooks up on bus 1 or 2.

Anyways, here's the end of my dmesg | tail.

[   54.246946] usb 4-4: new full speed USB device number 2 using ohci_hcd
[   54.565700] usbcore: registered new interface driver snd-usb-audio
[   54.574615] input: C-Media Electronics Inc.       USB PnP Sound Device as /devices/pci0000:00/0000:00:04.0/usb4/4-4/4-4:1.3/input/input5
[   54.574682] generic-usb 0003:0D8C:013C.0001: input,hidraw0: USB HID v1.00 Device [C-Media Electronics Inc.       USB PnP Sound Device] on usb-0000:00:04.0-4/input3
[   54.574694] usbcore: registered new interface driver usbhid
[   54.574696] usbhid: USB HID core driver

...new full speed... but using OHCI not EHCI.
Is there something I can do about this?  Different Modules?  UDev rules?
Maybe it's just false advertising, but it would be nice to get this thing working like it's -supposed- to.

Thanks

Last edited by eilenbeb (2011-12-06 19:18:15)

eilenbeb

Member

Registered: 2009-03-08

Posts: 44

Re: [solved, false advertising]USB 2.0 device showing up as USB 1.0 device

....just posting at myself here, it seems I was confused about something.

...new full speed...

was correct.

Low speed (USB 1.x) 1.5 Mb/sec.
Full speed (USB 1.x) 12 Mb/sec.
High speed (USB 2.0) 480 Mb/sec. (src=http://linux-usb.sourceforge.net)

No other progress on this yet.  In a few days I'll be able to test the device on other systems to see how it hooks up.
Also, the box the device came in 'claims' USB 2.0, but doesn't have the official branding as seen on usb.org, so I might'a got taken by bad marketing.

pigiron

Member

From: USA

Registered: 2009-07-14

Posts: 150

Re: [solved, false advertising]USB 2.0 device showing up as USB 1.0 device

Yep... the USB 2.0 claim seems to be a shady marketing gimmick.

If you go to the C-Media web page listing their chips:

http://www.cmedia.com.tw/ProductsIndex.aspx

You'll notice the following claim for all of their chips:

Cmedia supplies versatile choices of USB1.1 (USB2.0 full-speed compatible) audio solutions to compliment whichever type of device you want to design.

I also have a cheap USB 1.1 audio device using one of their chips (but a different chip than yours), but have not had any audio problems (yet).

My chip seems to be a CM119 and from poking around, it appears that yours may use a CM108 chip. If you download either chip's datasheet, it plainly states that it will register as a USB 1.1 device.

eilenbeb

Member

Registered: 2009-03-08

Posts: 44

Re: [solved, false advertising]USB 2.0 device showing up as USB 1.0 device

Hah, yep, I suspected as much.  Thanks for the reply & the info.
.
Guess I'll keep the thing since it doesn't have bad sound, and no noticable lag.
..time to go leave some buyer feedback...