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Re: [Qemu-devel] nonzero LUN on USB Bulk Only Transfer fails with QEMU+e
Re: [Qemu-devel] nonzero LUN on USB Bulk Only Transfer fails with QEMU+edk2
Tue, 19 Feb 2019 09:49:16 +0100
> (2) If I change the cmdline to "lun=5", then the exchange is:
Not supported (by the usb protocol).
The protocol has a control message to query the number of devices (grep
for GetMaxLun in qemu). LUNs are not allowed to be sparse. So, with a
single storage device the LUN must be zero. With two devices the LUNs
must be 0,1, with three 0,1,2 etc., you get the idea :)
Maybe usb-bot should check for that and throw an error, I think right
now we only have the generic scsi code check which will verify the lun
isn't too big (<= 15) but will not check the non-sparse requirement.