Created attachment 278267 UCSI altmode support patch The previous comment isn't entirely correct. UCSI notifications are broken, but the command failure I quoted has nothing to do with it, it was just an artefact. I do not know why they are broken.
It looks like the Linux UCSI driver does not support alternate modes. I wrote a patch against kernel tag 4.17 (attached) that adds support for requesting and setting alternate modes, if advertised by UCSI. It's hacky (more than one MID per SVID is probably broken, and activating modes via port partner sysfs node doesn't work) but it's sufficient for testing. Here's what I get in dmesg with the patch when plugging in the adapter: [856816.978580] ucsi_acpi USBC000:00: con1: found port altmode 8087:00000001 [856816.978606] ucsi_acpi USBC000:00: con1: found port altmode ff01:00001c46 [856817.128092] ucsi_acpi USBC000:00: con1: found port altmode 413c:00000001 [856817.282308] ucsi_acpi USBC000:00: con1: in altmode index 0 [856818.277557] ucsi_acpi USBC000:00: con1: found partner altmode 8087:00000001 It looks like the USB PD controller in XPS13 ignores the 05ac SVID in the ACK Disc PD message, and doesn't even try to request the altmode list for that SVID. This makes sense, because it doesn't support any Apple-specific altmodes. I'm now looking into reflashing the adapter such that it would advertise some SVID:MID pair that is recognized by XPS13. I don't actually know if there's any; if you know what other Thunderbolt adapters use, please share. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1726299 Title: Apple Thunderbolt 2 to FireWire adapter not working To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1726299/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
