Switchable graphics and radeon PX runtime

[Dave Airlie]

On 14 November 2014 18:12, Takashi Iwai <tiwai at suse.de> wrote:
> Hi Alex,
>
> we've got a few bug reports about the behavior of radeon driver on
> machines with Intel+AMD "switchable graphics" (no Muxless).  So far,
> it seems that the sane only way to make the machine working is to get
> back to the old vgaswitcheroo behavior via radeon.runpm=0.  Without
> it, radeon GPU gives a spurious output as connected, eventually
> crashes GNOME.  (Also, from the nature of the switchable graphics,
> vgaswitcheroo looks more intuitive to me.)

vgaswitcheroo only matters if there is a MUX, the point of it is to drive
the MUX.

dynamic poweroff makes more sense, switcheroo on/off switch was
just a hack.

> How are such machines supposed to work with the recent system?  Is PX
> wrongly detected on them, or something else missing?

It sounds like the connector is wrongly detected and that should be what
is fixed.

Dave.