On Sun, 2016-08-07 at 23:37 +0200, Pavel Machek wrote: > Hi! > > > > With these boards, you will not see anything on the screen that is > > > attached to a Type-C connector until the OS has booted to the point > > > where it has negotiated the power contract and entered a mode. > > > > > > If the system has BIOS/FW/EC capable of negotiating the power contract > > > and enter a mode, but where we still are expected to take over the > > > whole TCPM in OS, I think the connection will be reset. > > > > Think about a DP over type C display with a USB PD power brick on a > > daisy chain. > > If the host needs more than 15W or more than 5V, a reset is suicide. > > > > And losing earlyprintk hurts a lot. > > This means we need USB PD statically in the kernel. And a kernel > > based policy that brings up all displays. > > Yes please. > > Of course, even that will hurt, because I guess that means printk() > after USB, and that means late in the boot process, but better late in > kernel than in initrd. i can confirm that in a laptop with a decent firmware a docking station is switched into the mode that will make the display work. In principle all is well if we can manage a handover. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
