[Qemu-devel] Re: USB-OHCI / UHCI: Isochronous transfer not working on Linux host

[Thomas Bandelier]

Hi Arnon, Max, Pierre,

Arnon, Thanks for your feedback on this point.

As we need to manage several USB 2.0 devices in our environment, we are going to work on this aspect. We are very motivated to make it work.

Do you (Max and/or Arnon) have any idea of what should be done / reworked in order to support USB 2.0 devices and especially isochronous transfers in QEMU?

We would prefer keeping OHCI implementation, but do you think we should switch to UHCI? Or maybe EHCI?

If we can keep OHCI, what should we begin to do in order to debug current QEMU OHCI implementation? Same question for the other controllers if we have to switch.

Best Regards,

Thomas

On Fri, Nov 28, 2008 at 8:32 PM, Arnon Gilboa <address@hidden> wrote:

Hello Thomas,

 

Since the last time I sent a patch, usb-linux.c & usb-uhci.c were completly rewritten by

Max Krasnyansky and merged by aliguori.

 

However, looking at my post below from 24 Sep 2007, you can see that usb-uhci,

which is USB 1.1 host controller emulation, was mostly tested on USB 1.1 devices.

 

I am sure that many USB 2.0 and even several 1.1 devices (especially isochronous)

will NOT work with the emulation.

 

http://lists.gnu.org/archive/html/qemu-devel/2007-09/msg00409.html

 

Regards,
Arnon

---

From: Thomas Bandelier [mailto:address@hidden]
Sent: Thursday, November 27, 2008 4:06 PM
To: address@hidden
Cc: address@hidden; Arnon Gilboa
Subject: USB-OHCI / UHCI: Isochronous transfer not working on Linux host

Hi all,

Following several tests we did with qemu trunk, Isochronous transfer seems to be broken with the head of qemu.

We tried following Os (targets):
-WinXP (i386)
-Win2k (i386)
-Several linux kernel ( 2.6.26-1 (i386), 2.6.27 (ARM) )

On our host we are using Gentoo with 2.6.23 and 2.6.27 kernel.

Following USB devices were tested:
-USB 2.0 logitech webcams
-Terratec USB2.0 Cynergy hybrid XS FM tuner.

Both OHCI and UHCI configurations were tested in i386 target.
Only OHCI was tested in ARM target.

In all these configurations, it was never possible to initiate isochronous USB transfer. It was possible to enumerate the devices but as soon as isochronous packets were used, the procedure failed. It means for example that no picture was retrieved from the webcams, and no audio data was retrieved from FM tuner.

It is important to mention that all theses devices perfectly work on our host.

After some search in this maling list archives, it seems that no work has been made on these aspects since Arnon Gilboa sent some patches more than one year ago. Am I wrong?

So It would be very useful for us to have a feedback from the community on this point.
Has someone met the same problems? Has someone investigated this aspect?
Is someone regularly using this feature?

How can we investigate this problem?

Thanks

Thomas