[Intel-gfx] USB-C DP mode problem on linux

[Saarinen, Jani]

Hi,
What is exact gitlab issue for this, can you send link? 

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Andrzej Kre
> Sent: perjantai 13. marraskuuta 2020 22.28
> To: Deak, Imre <imre.deak at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Heikki Krogerus
> <heikki.krogerus at linux.intel.com>
> Subject: Re: [Intel-gfx] USB-C DP mode problem on linux
> 
> Got it.
> 
> Thank You for quick replying. Due to coronavirus I was not able to issue a ticket
> quickly . But I created it.
> 
> 
> Best Regards,
> 
> 
> wt., 20 paź 2020 o 16:25 Imre Deak <imre.deak at intel.com
> <mailto:imre.deak at intel.com> > napisał(a):
> 
> 
> 	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
>