> On 23 Nov 2017, at 5:24 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Nov 23, 2017 at 04:53:41PM +0800, Kai Heng Feng wrote: >> >> What I want to do here is to finding this connection: >> Realtek r8153 <-> SMSC hub (USD ID: 0424:5537) <-> >> ASMedia XHCI controller (PCI ID: 1b21:1142). >> >> Is there a safer way to do this? > > Nope! You can't do that at all from within a USB driver, sorry. As you > really should not care at all :) Got it :) The r8153 in Dell TB dock has version information, RTL_VER_05. We can use it to check for workaround, but many working RTL_VER_05 devices will also be affected. Do you think it’s an acceptable compromise? >> I have a r8153 <-> USB 3.0 dongle which work just fine. I can’t find any >> information to differentiate them. Hence I want to use the connection to >> identify if r8153 is on a Dell TB dock. > > Are you sure there is nothing different in the version or release number > of the device? 'lsusb -v' shows the exact same information for both > devices? Yes. I attached `lsusb -v` for r8153 on Dell TB dock, on a RJ45 <-> USB 3.0 dongle, and on a RJ45 <-> USB Type-C dongle. >> Yes. From what I know, ASMedia is working on it, but not sure how long it >> will take. In the meantime, I’d like to workaround this issue for the users. > > Again, it's a host controller bug, it should be fixed there, don't try > to paper over the real issue in different individual drivers. > > I think I've seen various patches on the linux-usb list for this > controller already, have you tried them? Yes. These patches are all in mainline Linux now. >> Actually no. >> I just plugged r8153 dongle into the same hub, surprisingly the issue >> doesn’t happen in this scenario. > > Then something seems to be wrong with the device itself, as that would > be the same exact electrical/logical path, right? I have no idea why externally plugged one doesn’t have this issue. Maybe it’s related how it’s wired inside the Dell TB dock... Kai-Heng
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> thanks, > > greg k-h
