[Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Erik Rull]

When enabling the -device usb-host option support for adding automatically 
USB devices from the host to the guest, only one device gets detected.
It does not matter if it is added via commandline or via device_add on the 
qemu console.

Curious: If a second devices is plugged into the host, nothing happens in 
qemu. But on the host, the device is detected. If the first device is 
removed, the second device gets detected by qemu. If then the first device 
is added again, it gets not detected by qemu until the second device is 
removed and so on.

When adding the devices manually, everything is fine.
Confirmed with and without the ehci-patch on qemu-kvm 0.14.0. I first sent 
the report to the kvm list but it seems to be a pure qemu related issue.

Best regards,

Erik

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Erik Rull]

No idea how to start here?
If someone could assist me where to start and what information to collect, 
I could help debugging and finding a solution for that.

Best regards,

Erik


Erik Rull wrote:
> When enabling the -device usb-host option support for adding
> automatically USB devices from the host to the guest, only one device
> gets detected.
> It does not matter if it is added via commandline or via device_add on
> the qemu console.
>
> Curious: If a second devices is plugged into the host, nothing happens
> in qemu. But on the host, the device is detected. If the first device is
> removed, the second device gets detected by qemu. If then the first
> device is added again, it gets not detected by qemu until the second
> device is removed and so on.
>
> When adding the devices manually, everything is fine.
> Confirmed with and without the ehci-patch on qemu-kvm 0.14.0. I first
> sent the report to the kvm list but it seems to be a pure qemu related
> issue.
>
> Best regards,
>
> Erik
>

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Erik Rull]

Hi all,

does nobody else struggle with this bug? I would like to help, but don't 
know where to start!

Best regards,

Erik


Erik Rull wrote:
> No idea how to start here?
> If someone could assist me where to start and what information to
> collect, I could help debugging and finding a solution for that.
>
> Best regards,
>
> Erik
>
>
> Erik Rull wrote:
>> When enabling the -device usb-host option support for adding
>> automatically USB devices from the host to the guest, only one device
>> gets detected.
>> It does not matter if it is added via commandline or via device_add on
>> the qemu console.
>>
>> Curious: If a second devices is plugged into the host, nothing happens
>> in qemu. But on the host, the device is detected. If the first device is
>> removed, the second device gets detected by qemu. If then the first
>> device is added again, it gets not detected by qemu until the second
>> device is removed and so on.
>>
>> When adding the devices manually, everything is fine.
>> Confirmed with and without the ehci-patch on qemu-kvm 0.14.0. I first
>> sent the report to the kvm list but it seems to be a pure qemu related
>> issue.
>>
>> Best regards,
>>
>> Erik
>>
>
>

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Gerd Hoffmann]

   Hi,

>>> When enabling the -device usb-host option support for adding
>>> automatically USB devices from the host to the guest, only one device
>>> gets detected.

Yes.  -device usb-host creates a *single* virtual usb device instance. 
When a matching device on the host is found the virtual device is 
plugged in, otherwise it is plugged out.  In plugged out state qemu 
looks now and then (every two seconds IIRC) whenever a matching device 
was plugged into the host.

Try -device usb-host twice if you need two virtual usb devices.

cheers,
   Gerd

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Erik Rull]

Gerd Hoffmann wrote:
>   Hi,
>
>>>> When enabling the -device usb-host option support for adding
>>>> automatically USB devices from the host to the guest, only one device
>>>> gets detected.
>
> Yes. -device usb-host creates a *single* virtual usb device instance.
> When a matching device on the host is found the virtual device is
> plugged in, otherwise it is plugged out. In plugged out state qemu looks
> now and then (every two seconds IIRC) whenever a matching device was
> plugged into the host.
>
> Try -device usb-host twice if you need two virtual usb devices.
>
> cheers,
> Gerd

Hi Gerd,

hm, if I add it multiple times and plug in a USB flashdrive, then all slots 
are filled up with this device (duplicated)...
And Windows detects them with the result, that the "not first" devices are 
marked with a yellow exclamation mark in the device manager.
And the next device plugged in gets then not detected because all 
preallocated slots are full :-(

Any ideas?

Best regards,

Erik

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[Gerd Hoffmann]

> Hi Gerd,
>
> hm, if I add it multiple times and plug in a USB flashdrive, then all
> slots are filled up with this device (duplicated)...
> And Windows detects them with the result, that the "not first" devices
> are marked with a yellow exclamation mark in the device manager.
> And the next device plugged in gets then not detected because all
> preallocated slots are full :-(
>
> Any ideas?

The upcoming usb patches will add the option to assign devices by 
physical host port, that is probably the best solution for the issue.

I don't have an idea offhand for stable-0.14 though.

cheers,
   Gerd

Re: [Qemu-devel] BUG: 0.14.0 -device usb-host supports only one device

[erik.rull]

Hi Gerd,

sorry, but that parameter causes a non-complete boot of my Windows VM (I
have removed that) when using the ehci-patch.

Additionally, the ehci patch does not support that parameter type, there
you must add it via -usbdevice host:auto:*.*

Any ideas how to proceed?
I need the ehci patch because it removes the bluescreen issue when plugging
in USB 2.0 printers even if USB 2.0 is disabled in the host bios and the
USB 1.1 transfer performance is less that 64k/sec without the patch.

Best regards,

Erik