keg55 wrote:
I totally understand both points 1 and 2. However, when plugging a USB 3.0 in first USB 3 should be used in the 'daisy chain'. However, that was NOT the case for me. I plugged the 3.0 device in first and the 2.0 second. I unplugged the 2.0 device out first; then unplugged the 3.0 device. So, the next time I plugged in my 3.0 device, I expected the 'daisy chain' hub to be 3.0 as defined in point 1 above. That didn't happen. I had to use point 3 abo ve to get the right side back to 3.0.
So, I disagree this is how it is suppose to behave.
So I can understand this, the first device in a daisy chain will determine the speed of operation of the devices further down the daisy chain, which has been the case with USB for quite some time. But the test you described didn't involve daisy chaining; rather, the left USB 3.0 port got a real USB 3.0 drive while the right USB 3.0 port got a USB 2.0 drive and both operated at their correct speeds. It sounds like you then moved the USB 3.0 device to the port the USB 2.0 device had been connected to and instead of getting USB 3.0 speeds, you got USB 2.0 speeds.
KB HT5172 seems to apply to daisy chaining but "The first device you plug in will configure the port, so always connect USB 3 capable hubs or devices first" could also be understood to mean that port configuration is persistent, so what gets plugged in next is stuck with the setting that's already been established after the first device is removed. The solution you found is more subtle, first because "Sometimes unplugging and plugging the device back in can resolve the issue" is not offered as the solution to the problem you had, and second because "unplugging and plugging the device" could mean the device and cable or just the device (without your discovery, I'd just unplug the cable from the port, and that wouldn't work). Indeed, the issue you discovered isn't even acknowledged in HT5172.
So one question is whether the computer's USB 3.0 port should be expected to negotiate anew every time a device is plugged directly into it, or must your renegotiating technique be used? Another question is do the two ports negotiate their capabilities separately and retain the settings separately?
Finally, if the port is set for USB 3.0, the device is also 3.0 and the device contains a bootable partition, can the computer be made to boot from the device at USB 3.0 speeds?