Re: [PATCH 1/2] vga_switcheroo: add power support for windows 10 machines.

From: Alex Deucher <alexdeucher@gmail.com>
To: Dave Airlie <airlied@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: Re: [PATCH 1/2] vga_switcheroo: add power support for windows 10 machines.
Date: Mon, 14 Mar 2016 10:30:50 -0400	[thread overview]
Message-ID: <CADnq5_PMS+TV_csWMXGNN=aQ=GE6ATXij2beNZb-dFisBUsfUw@mail.gmail.com> (raw)
In-Reply-To: <CAPM=9txo4aOOa-CS-mnyQe+vYDtAOCm1bzAgfMzwJJS8ZuYmwQ@mail.gmail.com>

On Sun, Mar 13, 2016 at 10:19 PM, Dave Airlie <airlied@gmail.com> wrote:
> On 11 March 2016 at 23:45, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> On Friday, March 11, 2016 12:58:15 PM Mika Westerberg wrote:
>>> On Thu, Mar 10, 2016 at 09:57:09PM +0100, Rafael J. Wysocki wrote:
>>> > > It doesn't seem to do any runtime PM,
>>> > > I do wonder if pcieport should be doing it's own runtime PM handling,
>>> > > but that is a
>>> > > larger task than I'm thinking to tackle here.
>>> >
>>> > PCIe ports don't do PM - yet.  Mika has posted a series of patches to implement
>>> > that, however, that are waiting for comments now:
>>> >
>>> > https://patchwork.kernel.org/patch/8453311/
>>> > https://patchwork.kernel.org/patch/8453381/
>>> > https://patchwork.kernel.org/patch/8453391/
>>> > https://patchwork.kernel.org/patch/8453411/
>>> > https://patchwork.kernel.org/patch/8453371/
>>> > https://patchwork.kernel.org/patch/8453351/
>>> >
>>> > > Maybe I should be doing
>>> > >
>>> > > pci_set_power_state(pdev->bus->self, PCI_D3cold) ? I'm not really sure.
>>> >
>>> > Using pci_set_power_state() would be more appropriate IMO, but you can get
>>> > to the bridge via dev->parent too, can't you?
>>> >
>>> > In any case, it looks like you and Mika need to talk. :-)
>>>
>>> When the vga_switcheroo device gets runtime suspended (with the above
>>> runtime PM patchs for PCIe root ports) the root port should also be
>>> runtime suspended by the PM core.
>>
>> Right, after your patches have been applied, the additional handling
>> won't be needed.
>>
>> So Dave, maybe you can check if the Mika's patches help?
>
> Hi Mika,
>
> I tested your patches with a couple of changes on the Lenovo W541.
>
> The attached patch contains the two things I needed to get the same
> functionality
> as my patches.
>
> I'm really not in love with the per-chipset enablement for this,
> really any chipsets
> after a certain year should probably be better, as we'll constantly be
> adding PCI Ids
> for every chipset ever made, and I expect we'll forget some.

Yeah, I don't care of that either.  There are always going to be
chipsets falling through the cracks.

Alex

>
> Dave.
>
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