So I am not sure what DP alt mode is here, but I can confirm a regression with the 3.06 beta upgrade that I have witnessed on my 12th gen laptop. The symptom is that a USB-A card stops working after suspend (deep or idle, Linux 6.0 on Debian bookworm). Unplugging the card and plugging it back in fixes the problem.
I am not the only one with this problem, first reported in [RESOLVED] USB-A Expansion Card stops working until unplugged. I am not sure it’s the same problem as the one describe in the original post here, because the post talks about Windows and a USB-C port, while I’m on Linux and, well, technically it’s both a USB-C port and a USB-A port (because it’s a USB-A card plugged in a USB-C port), but anyways, I figured it was worth mentioning the thread here.
I have tried the suggested method: shutting down the computer for two minutes and booting back up does bring the USB-A port, but that is a poor consolation as the problem, I suspect will just return later on (although I have yet to confirm that). It’s a much easier workaround to yank the card out and put it back in, that brings it back online reliably.