[PATCH 1/2] drm/amdgpu: fix power state when port pm is unavailable

[Peter Wu]

On Wed, Nov 23, 2016 at 12:01:55PM -0500, Alex Deucher wrote:
>  On Tue, Nov 22, 2016 at 8:22 PM, Peter Wu <peter at lekensteyn.nl> wrote:
> > When PCIe port PM is not enabled (system BIOS is pre-2015 or the
> > pcie_port_pm=off parameter is set), legacy ATPX PM should still be
> > marked as supported. Otherwise the GPU can fail to power on after
> > runtime suspend. This affected a Dell Inspiron 5548.
> >
> > Ideally the BIOS date in the PCI core is lowered to 2013 (the first year
> > where hybrid graphics platforms using power resources was introduced),
> > but that seems more risky at this point and would not solve the
> > pcie_port_pm=off issue.
> >
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98505
> > Reported-and-tested-by: Nayan Deshmukh <nayan26deshmukh at gmail.com>
> > Signed-off-by: Peter Wu <peter at lekensteyn.nl>
> > ---
> > Hi,
> >
> > This patch is already three weeks old. One alternative idea was lowering BIOS
> > date in PCI core, but as pcie_port_pm=force did not have the desired effect, I
> > do not think that this would help though.
> 
> Thanks for doing this.
> 
> >
> > I have also not contacted linux-pci or Mika about lowering the year due to the
> > lack of a good reason.  Might do it later though once ACPICA bug 1333 is sorted
> > out such that lowering the year actually has benefits for a Nvidia laptop (or if
> > some amdgpu problem can be solved by this).
> >
> > Both patches should probably be Cc stable (4.8+), fixing 2f5af82eeab2 and
> > b8c9fd5ad4b4 ("track whether if this is a hybrid graphics platform"). There have
> > been some ifdef 0's and reverts in between, so I was not sure if adding the
> > Fixes tag is appropriate.
> 
> I don't think we need to cc stable.  In kernel 4.8 we don't attempt to
> do d3cold at all.  4.8 and older kernels have:
> c63695cc5e5f685e924e25a8f9555f6e846f1fc6 (drm/amdgpu: work around lack
> of upstream ACPI support for D3cold)
> which was reverted for 4.9.

That patch was already reverted in 4.8 as far as I can see:

$ git tag --contains c39b487f195b93235ee76384427467786f7bf29f | grep v4.8
v4.8

Can you double-check? v4.8 was the first kernel with D3cold support in
PCI core.

> Series is:
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

Thanks!

Kind regards,
Peter

> 
> >
> > Kind regards,
> > Peter
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
> > index 10b5ddf..951addf 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
> > @@ -33,6 +33,7 @@ struct amdgpu_atpx {
> >
> >  static struct amdgpu_atpx_priv {
> >         bool atpx_detected;
> > +       bool bridge_pm_usable;
> >         /* handle for device - and atpx */
> >         acpi_handle dhandle;
> >         acpi_handle other_handle;
> > @@ -200,7 +201,11 @@ static int amdgpu_atpx_validate(struct amdgpu_atpx *atpx)
> >         atpx->is_hybrid = false;
> >         if (valid_bits & ATPX_MS_HYBRID_GFX_SUPPORTED) {
> >                 printk("ATPX Hybrid Graphics\n");
> > -               atpx->functions.power_cntl = false;
> > +               /*
> > +                * Disable legacy PM methods only when pcie port PM is usable,
> > +                * otherwise the device might fail to power off or power on.
> > +                */
> > +               atpx->functions.power_cntl = !amdgpu_atpx_priv.bridge_pm_usable;
> >                 atpx->is_hybrid = true;
> >         }
> >
> > @@ -471,6 +476,7 @@ static int amdgpu_atpx_power_state(enum vga_switcheroo_client_id id,
> >   */
> >  static bool amdgpu_atpx_pci_probe_handle(struct pci_dev *pdev)
> >  {
> > +       struct pci_dev *parent_pdev = pci_upstream_bridge(pdev);
> >         acpi_handle dhandle, atpx_handle;
> >         acpi_status status;
> >
> > @@ -485,6 +491,7 @@ static bool amdgpu_atpx_pci_probe_handle(struct pci_dev *pdev)
> >         }
> >         amdgpu_atpx_priv.dhandle = dhandle;
> >         amdgpu_atpx_priv.atpx.handle = atpx_handle;
> > +       amdgpu_atpx_priv.bridge_pm_usable = parent_pdev && parent_pdev->bridge_d3;
> >         return true;
> >  }
> >
> > --
> > 2.10.2