Hi, On Mon, Oct 19, 2020 at 05:24:59PM +0300, Heikki Krogerus wrote: > Hi Andrzej, > > On Sat, Oct 17, 2020 at 01:34:54PM +0200, Andrzej Kre wrote: > > Hi, > > > > I know that You were involved in working on USB-C DP drivers. > > You are my last chance to resolve my issue. > > > > On my HP laptop I have Intel UHD Graphics 620. > > When I'm connecting my 4K monitor to Display Port. It is assigning to > > DP-2-2 socket and I have full 3840x2160 with 60.00Hz > > But, when I'm connecting the same monitor to the USB-C port, then it is > > connecting to the DP-1 socket and the maximum that it can achieve is > > 3840x2160 with only 30.00Hz. > > But I'm making some trick: I'm connecting the same monitor through HDMI, so > > it is connecting to DP-1 socket, and simultaneously I'm connecting USB-C, > > and now USB-C is connecting to DP-2-2 socket (because DP-1 is occupied by > > HDMI) and I can have full 4K with 60Hz. > > Please, help me, how to force USB-C to connect always to DP-2-2 socket? > > Or do You know maybe where is the problem? > > Unfortunately we have no control over the mux in the operating system > on Skylakes, at least in USB subsystem. It all happens in firmware. > Maybe graphics side can do something. > > Adding Jani, Imre, Ville and the Intel GFX list. On SKL/KBL the USB-C -> native DP/HDMI conversion is done by an off-CPU chip and the display driver doesn't have a way either to affect the muxing. Not sure why things work on DP-2 and not on DP-1, there is no port specific limits on the CPU side that would explain this. There is a link training failure in the log, so would be good to see more details on that. Could you file a ticket at https://gitlab.freedesktop.org/drm/intel/-/issues providing a full log booting with drm.debug=0x1e for the working and non-working cases? Thanks, Imre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
