Control: tags -1 + moreinfo Hi,
On Wed, Aug 05, 2026 at 09:49:39AM +0200, Wenceslao Grillo wrote: > *Update: tested with bookworm's 6.1.0-50-amd64 kernel on Debian 13* > > I installed |linux-image-6.1.0-50-amd64| from bookworm alongside the Trixie > system and booted into it via GRUB (|uname -r| confirms |6.1.0-50-amd64|). > > Result: the external monitor works correctly with a single direct > USB-C-to-USB-C cable, with the laptop on its own charger — i.e. it > reproduces the Debian 12 behavior, not the Debian 13 (6.12) regression. No > secondary USB-B cable is needed. > > Note: on this kernel, |/sys/class/typec/| is empty even though |ucsi_acpi|, > |typec_ucsi|, and |typec| are all loaded (confirmed via |lsmod|). So I can't > provide the svid/power_role/number_of_alternate_modes comparison here. > > dmesg shows: > > |[ 6.478666] ucsi_acpi USBC000:00: PPM init failed (-110)| > > This may or may not be related to the ACPI/WMI method failures I noted in > the original report (|AE_AML_BUFFER_LIMIT| errors on |\_SB.WMID.WQBE| and > |\HWMC|, and |hp_bioscfg| error |0x300a|) . > > With the kernel 6.12.96+deb13-amd64 I get this: > > dmesg | grep -i -E "ucsi|typec" > [ 1.330833] typecport0: bound usb3-port2 (ops connector_ops [usbcore]) > [ 1.330859] typecport0: bound usb2-port1 (ops connector_ops [usbcore]) > [ 1.916979] typecport1: bound usb3-port3 (ops connector_ops [usbcore]) > [ 1.917021] typecport1: bound usb2-port2 (ops connector_ops [usbcore]) > > And the monitor is back to not working without an additional USB cable for > power. (Although, when I first rebooted with the 6.12, it worked, until I > disconnected it and connected it back again, so it seems the problem is > right at the negotiation stage, and once that's been done the monitor is > happy to go on working). > > I couldn't find any kernels between 6.1 and 6.12 in apt. Claude AI suggests > using an Ubuntu repository. To me that sounds odd at least, but I'm way out > of my depth here. If you send me more instructions, I'll be happy to help. No that is indeed not what we want. There is the Debian snapshot service, which provide an archive of all released packages: https://snapshot.debian.org/package/linux-signed-amd64/ >From here you can fetch other intermediate linux image packages. Could you please as well add to the Debian bug the full kernel logs in both cases (i.e. 6.1.y and 6.12.101 ideally, up to where the USB monitor does not work anymore). Having both logs to compare might give us already some advance help. Regards, Salvatore
