Re: [Qemu-devel] Revert commit 5af35d7feccaa7d26b72c6c3d14116421d736b36 - "usb-host-libusb: Fix reset handling"

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 10-02-15 22:02, Dennis Ostermann wrote:
> Hello Hans,
>
> thanks for taking care.
>
>
> 09-02-15 09:09, Hans de Goede wrote:
>> Hi,
>>
>> On 09-02-15 22:09, Dennis Ostermann wrote:
>>> Hi there,
>>>
>>> please revert commit 5af35d7feccaa7d26b72c6c3d14116421d736b36 - "usb-host-libusb: Fix reset handling"
>>>
>>> This breaks usb pass through of FTDI based usb devices:
>>>
>>> On the host:
>>>
>>> lsusb | grep FT2232
>>> Bus 003 Device 008: ID 0403:6010 Future Technology Devices International, Ltd FT2232C Dual USB-UART/FIFO IC
>>>
>>>
>>> ~/qemu-install/bin$ sudo ./qemu-system-x86_64 -monitor telnet:127.0.0.1:1234,server,nowait -hda /dev/sdd2 -redir tcp:20022::22 --enable-kvm -cpu host -smp 4 -vga vmware --vnc :0 -m 8192  -usb -device usb-ehci,id=ehci -device usb-host,bus=ehci.0,vendorid=0x0403,productid=0x6010
>>> WARNING: Image format was not specified for '/dev/sdd2' and probing guessed raw.
>>>            Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
>>>            Specify the 'raw' format explicitly to remove the restrictions.
>>> libusbx: error [_get_usbfs_fd] libusbx couldn't open USB device /dev/bus/usb/003/005: No such file or directory
>>> libusbx: error [_get_usbfs_fd] libusbx couldn't open USB device /dev/bus/usb/003/006: No such file or directory
>>> libusbx: error [_get_usbfs_fd] libusbx couldn't open USB device /dev/bus/usb/003/007: No such device
>>>
>>> The device gets reset again and again and is re-enumerated every time and finally not passed through.
>> This looks like the device drops of the bus when it is reset, that is not normal behavior,
>> there seems to be something unique to your setup causing this. Have you tried this on
>> multiple machines / different usb ports on your pc ? This may be something weird with the usb
>> controller in your machine.
> The machine uses Intel H97 chipset, so not that unique. I tried every port, every USB BIOS, with and without hub, it doesn't make any difference. But you're right, I also tried it on a T61 with Intel 900 series chipset and it worked alright. But this is an 'old' USB 2.0 chipset. I'll try on another box with USB 3.0 chipset tomorrow, if I can get one.

Ok, lets wait and see what results another model usb-3 capable pc / laptop gets us, I've
the feeling that this is a machine specific issue. Normally a usb-reset should not cause
a device disconnect as you're seeing here.

Regards,

Hans