Re: [Intel-gfx] Intel Arc A370M vs Linux 5.19

From: Daniel J Blueman <daniel@quora.org>
To: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [Intel-gfx] Intel Arc A370M vs Linux 5.19
Date: Thu, 15 Sep 2022 22:40:59 +0800	[thread overview]
Message-ID: <CAMVG2svdhBp-UU2L=Zofq2qgzapwvYGbXMZxtOTzK0T+2aLMHw@mail.gmail.com> (raw)
In-Reply-To: <YyMyKsy2XdInzarL@intel.com>

On Thu, 15 Sept 2022 at 22:09, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> On Thu, Sep 15, 2022 at 09:08:08PM +0800, Daniel J Blueman wrote:
> > Dear Intel et al,
> >
> > With a HP Spectre x360 16 16-f1xxx/891D (Intel i7-1260P) with an Arc
> > A370M GPU [1] running the latest Ubuntu 22.10 5.19.0-15-generic
> > kernel, we see:
> >
> > i915 0000:03:00.0: Your graphics device 5693 is not properly supported
> > by the driver in this kernel version. To force driver probe anyway,
> > use i915.force_probe=5693
> >
> > Since the GPU is unmanaged, battery life is around 30% of what it
> > could be. Unsurprisingly, adding i915.force_probe=5693 causes
> > additional  issues. Given a lack of BIOS option to disable the GPU, is
> > there any advice for Linux support or at least putting the GPU into
> > D3? I see only Windows drivers on the official support page [2], and
> > Linux 6.0-rc5 isn't buildable [3].
>
> I believe this is what you are looking for:
>
> echo auto | sudo tee /sys/bus/pci/devices/0000\:03\:00.0/power/control
>
> In Linux the default is to keep the unmanaged devices in D0.
> But changing the rpm to auto should transition the device to D3.
>
> You can go further and check with the lspci -vv if there are other
> unmanaged devices in the same pci root tree and also add them to the
> 'auto' rpm so you can even achieve D3cold in that whole device, what
> gives you extra power savings.
>
> I hope this helps for now.

Yes, I was also hoping this would work as we see D3hot is supported:

# echo auto > /sys/bus/pci/devices/0000\:03\:00.0/power/control
# lspci -vvvs 03:00.0
...
Capabilities: [d0] Power Management version 3
        Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA
PME(D0+,D1-,D2-,D3hot+,D3cold-)
        Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
                ^^

However it stays in D0 with PME disabled as we see. "Kernel modules:
i915" may suggest the i915 driver holds a reference to it, preventing
the transition.

Dan
-- 
Daniel J Blueman