[Intel-gfx] Intel Arc A370M vs Linux 5.19

[Daniel J Blueman]

On Thu, 15 Sept 2022 at 22:55, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
>
> On Thu, Sep 15, 2022 at 10:40:59PM +0800, Daniel J Blueman wrote:
> > On Thu, 15 Sept 2022 at 22:09, Rodrigo Vivi <rodrigo.vivi at 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.
>
> Oh, yes. I was thinking more on using the command line I sent when
> the i915 is not probed. i.e. without using the force probe. your first
> scenario.

My bad - a reference is held when lspci shows "Kernel driver in use:
..." which is not the case here. Accordingly, we see:
# ls /sys/bus/pci/drivers/i915
0000:00:02.0 bind  module  new_id  remove_id  uevent  unbind
...ie no "0000:03:00.0" to unbind.

> With the i915 loaded I'd like to see the dmesg and a few of the debugfs
> files under: /sys/kernel/debug/dri/0

Sure, see:
https://quora.org/a370m/{dmesg.txt,i915-debug.txt}
https://quora.org/a370m/{dmesg-forceprobe.txt,i915-debug-forceprobe.txt}

Thanks,
  Dan
--
Daniel J Blueman