[Nouveau] [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

On Mon, May 30, 2016 at 07:03:46PM +0200, Peter Wu wrote:
> On Sun, May 29, 2016 at 05:50:06PM +0200, Lukas Wunner wrote:
> > How exactly did you reach the situation where the root port didn't wake
> > up when you tried to load nouveau again? (IRC conversation this week.)
> 
> Ensure that the pci/pm patches are applied, then:
> 
>  0. Unload nouveau (I have blacklisted it for testing).
>  1. Enable rpm for the root port and children (control = auto).
>  2. Verify in the kernel logs that the devices are sleeping:
>         pcieport 0000:00:01.0: power state changed by ACPI to D3cold
>  3. (Optional, to rule out issues with delays:) Disable rpm for the
>     Nvidia device (control = on).
>  4. modprobe nouveau.
> 
> The above test with v4.6 + 4 pci/pm patches (8b71f565) gives:
> 
>     50.245795 MXM: GUID detected in BIOS
>     50.245948    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
>     50.246016 ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246044    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
>     50.246110    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246256 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246289    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246443 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246457    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246932 pci 0000:01:00.0: optimus capabilities: enabled, status dynamic power, hda bios codec supported
>     50.247005 VGA switcheroo: detected Optimus DSM method \_SB_.PCI0.PEG0.PEGP handle
>     50.247084    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PG00._ON] at AML address ffffc9000001086e length 11D
>     50.390140 pcieport 0000:00:01.0: power state changed by ACPI to D0
>     50.491893    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._DSW] at AML address ffffc90000010a2d length 1D
>     50.492285 pcieport 0000:00:01.0: PME# disabled
>     50.492583 nouveau 0000:01:00.0: unknown chipset (ffffffff)
>     50.492687 nouveau: probe of 0000:01:00.0 failed with error -12

I've tested this on a MacBook Pro, which does not have ACPI _PR3
methods for the root port to which the discrete GPU is attached.
The port can thus only suspend to D3hot, not D3cold.

Even without patch [2/9], when unloading nouveau and letting the
root port go to D3hot, the port is subsequently correctly resumed
to D0 when reloading nouveau.

So the issue that you're seeing without patch [2/9] seems to be
specific to Optimus/_PR3 machines. If possible you should try to
get it working without patch [2/9] because that patch is really
optional (as I've written in the commit message). I'm totally
unfamiliar with Optimus but maybe lspci could help to debug this?

Lukas