Linux 4.4.4 [regression]

[Deucher, Alexander]

> -----Original Message-----
> From: Jörg-Volker Peetz [mailto:jvpeetz at web.de]
> Sent: Monday, March 07, 2016 12:40 PM
> To: Deucher, Alexander; 'Linus Torvalds'; Dave Airlie; DRI mailing list
> Cc: Greg KH; Linux Kernel Mailing List; stable; lwn at lwn.net; Andrew Morton;
> Jiri Slaby
> Subject: Re: Linux 4.4.4 [regression]
> 
> Deucher, Alexander wrote on 03/07/16 17:44:
> >> -----Original Message-----
> >> From: linus971 at gmail.com [mailto:linus971 at gmail.com] On Behalf Of
> Linus
> >> Torvalds
> >> Sent: Monday, March 07, 2016 11:21 AM
> >> To: Jörg-Volker Peetz; Dave Airlie; DRI mailing list
> >> Cc: Greg KH; Linux Kernel Mailing List; Andrew Morton; stable;
> lwn at lwn.net;
> >> Jiri Slaby; Deucher, Alexander
> >> Subject: Re: Linux 4.4.4 [regression]
> >>
> >> On Mon, Mar 7, 2016 at 6:20 AM, Jörg-Volker Peetz <jvpeetz at web.de>
> >> wrote:
> >>>
> >>> This same problem with X does happen in 4.5-rc7. And removing the line
> >>> introduced by patch b36e52c44ce6728824546d8b5f05b844cede96f1
> makes
> >> X go again on
> >>> my laptop.
> >>
> >> Ok, so that's dbb17a21c131eca94eb31136eee9a7fe5aff00d9 in mainline.
> >>
> >> Dave, Alex: that commit makes Jörg-Volker's HP Pavilion dv7 with
> >> hybrid graphics (AMD HD 4200 - AMD 5400) unable to run X. No
> >> suspend/resume in sight, just starting X hangs.
> >>
> >> I'd guess it's the "radeon_switcheroo_set_state()" craziness (based on
> >> that hybrid graphics thing), but we need to do something since this is
> >> a regression.
> >>
> >> Just revert for now? Or do you have other suggestions for Jörg-Volker to
> >> test?
> >
> > Can you attach your dmesg output?
> >
> I append the dmesg output from 4.5-rc7 (as vacuous as it is) and from my
> running
> system with 4.4.4 without the problematic code line.
> Will try your attached patch next.

Thanks.  The patch won't make any difference in the case of your system.  It looks like you have a muxed system so I suspect what's happening is that one of the display is being reported as connected for both the IGP and the dGPU and then the desktop environment gets confused or there some sort problem in the detect functions since the mux is not switched to the dGPU.  I don't see an easy fix unless Dave has any ideas.  I'd say just revert for now. 

Alex