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

[Deucher, Alexander]

> -----Original Message-----
> From: Peter Wu [mailto:peter at lekensteyn.nl]
> Sent: Wednesday, November 23, 2016 12:13 PM
> To: Alex Deucher
> Cc: amd-gfx list; Deucher, Alexander; Nayan Deshmukh
> Subject: Re: [PATCH 1/2] drm/amdgpu: fix power state when port pm is
> unavailable
> 
> 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.

You are right.  I was thinking d3cold went upstream in 4.9, so yes, we should apply this to 4.8.

Alex

> 
> > 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