virtualbox.org

Hi, there,

I'm using gentoo, kernel 4.4.26, VB version 5.1.10. Also I have an external disk seagate 3tb st3000dm001 in its native external enclosure (with usb3). I get a contradiction. On the host (gentoo) it is seen as a disk ONLY if the module "uas" (USB attached SCSI) is loaded. Otherwise, only as some usb controller. In the guest (w7pro) it appears as a disk ONLY if the "uas" module of the host is disabled. Otherwise, again only as some attached usb device. I could reproduce it several times in a row. With and w/o a reboot.

Technically I can insert/remove the "uas" module depending on a situation. But this is not a proper solution for sure. Given I have two external drives like I have, and given I want to have one seen in the host and one in the guest I cannot achieve it (did not try explicitly but logically it will happen like that). Also, I'm not sure is it a problem of "uas" module or VB, but the pattern is clear.

I opened a bug report #16261 but was redirected here.

Any suggestions to solve/improve this behaviour?

Best, Alex

Windows 7 has no notion of USB streams and hence UAS.

Windows 7 has no notion of USB streams and hence UAS.

Well, but what can be done then? I understand your reply as it is not a bug but a feature. Is it correct to say that VBox is not the reason of the problem?

If it is as such, are you aware whether "uas" module can be disabled on per-device basis? I understand it is a not genuine VBox question but still.

Thanks in advance and the best,
Alex

alex-kas wrote:

Windows 7 has no notion of USB streams and hence UAS.

Well, but what can be done then?

Install a guest OS that has native support for UAS?

According to Wikipedia, Microsoft added UAS support in Windows 8. Perhaps you can find drivers for earlier versions.

To be honest, I do not understand why the host drivers should matter at all. USB passthrough should re-initialize the device and load the guest's drivers. Note "should", because the 'B' in 'USB' stands for Bugs.

Well, if "USB passthrough should re-initialize the device and load the guest's drivers" then my problem is how VBox handles the presence of "uas" module.

If VBox by construction accepts uas interface and then works with it, then the guest must have a support for uas, which most likely it (w7pro) has not.

So, yes, I cannot say I understand why VBox does not (or cannot) reinitialize a usb device bypassing any host (linux) kernel auxiliary interfaces? Is it a current design, limitation, or a bug? Note that upgrading to v8 is not an option to me. I must arrange the work with a linux host and a w7pro guest.

alex-kas wrote:Well, if "USB passthrough should re-initialize the device and load the guest's drivers" then my problem is how VBox handles the presence of "uas" module.

It doesn't. VirtualBox does not care what drivers are loaded on the host, it tries to kick out the host drivers, reset the USB device, and load the guest's drivers. But USB being USB, that doesn't always fully reinitialize the device.

Note that upgrading to v8 is not an option to me. I must arrange the work with a linux host and a w7pro guest.

No UAS in the guest then, simple.

What happens if you create a filter for the drive you want to pass through to the guest? Then if you plug it in, the host's drivers should not get loaded.

Why not post the 'lsusb -v' output for your troublemaking disk...