[Intel-gfx] [PATCH v5 00/12] Enable GPU switching on pre-retina?MacBook Pro

[Bastien Nocera]

On Mon, 2016-03-14 at 13:41 +0100, Lukas Wunner wrote:
> 
<snip>
> > So I'd push DIGD to the switch sysfs entry on boot. But I'm
> > guessing
> > that won't turn off the other output we're not interested in.
> IGD and DIGD switch to the integrated GPU and also turn off the
> discrete
> GPU. However if the machine is already switched to the integrated
> GPU,
> the commands are no-ops and the discrete GPU is not turned off.
> 
> In other words you need to check (by reading the switch file) which
> GPU
> the machine is switched to. If it's the integrated GPU, write OFF to
> the
> switch file. If it's the discrete GPU, write DIGD to the switch file.
> 
> Once runtime pm works, writing DIGD is sufficient.

I tested the runtime patches for Radeon on top of 4.6.0-rc2, and
writing DIGD failed. I also saw a number of messages with the
vga_switcheroo core in the kernel trying to switch GPUs but failed
because "client 1" was keeping it busy.

Is there any way to see what this "client 1" actually is? I'm guessing
plymouth. In any case, once I'm logged in, the "DIS" is powered and
used, and the IGD is powered as well.

Cheers