RE: [Qemu-devel] USB storage cannot be recognized on guest Linuxdomain?

["Yu, Xiaoyang" <xiaoyang.yu@intel.com>]

Lonnie,

Thank you so much for write the patch for me! It works well with Fedora Core 4. Since it added UHCI suspend/resume support, so I guess it should also work with Windows XP :-)

Thanks
Xiaoyang
 

-----Original Message-----
From: qemu-devel-bounces+xiaoyang.yu=intel.com@nongnu.org [mailto:qemu-devel-bounces+xiaoyang.yu=intel.com@nongnu.org] On Behalf Of Lonnie Mendez
Sent: 2007年2月15日 22:49
To: qemu-devel@nongnu.org
Subject: RE: [Qemu-devel] USB storage cannot be recognized on guest Linuxdomain?

On Thu, 2007-02-15 at 15:44 +0800, Yu, Xiaoyang wrote:
> Hi Lonnie,
> 
> Thanks a lot for the information.
> 
> In our use case, we do not know the USB disk information before it is plugged by customer, so we cannot start qemu with -usbdevice.
> 
> For Linux, reload the uhci_hcd driver works. If we use this solution in our use case, then we need to issue an interrupt (maybe by pic_set_irq_new?) to the guest OS when QEMU detect a USB device is attached, and then the guest OS will reload the uhci_hcd driver. Is that right? Currently there is something wrong with the list archive server, so I haven't search out any example code from it :-(
> 
> I found that there is a patch to add the UHCI suspend/resume support in the archive posted by you, but it cannot be applied to QEMU-DM 0.8.2 directly:
> http://lists.gnu.org/archive/html/qemu-devel/2006-04/msg00576.html
> 
> I wonder why there is no official UHCI suspend/resume support in QEMU. To reload the uhci_hcd driver seems to be only a work around. Sometimes it even cause kernel oops. 
> 
> I also wonder why the kernel 2.6.11-1.1369_FC4 can recognize USB storage without UHCI suspend/resume support.

The attached patch is enough to have a device on linux recognized after
usb_add.  However, the device must be attached to the uhci controller's
root hub.  If a device is attached to an emulated usb hub device it will
not be detected.