[PATCH] drm/amdgpu: Add a new module param to disable d3cold

[Alex Deucher]

On Thu, Nov 30, 2023 at 1:29 AM Ma, Jun <majun at amd.com> wrote:
>
> Hi Alex,
>
> On 11/30/2023 12:39 AM, Alex Deucher wrote:
> > On Wed, Nov 29, 2023 at 11:37 AM Ma Jun <Jun.Ma2 at amd.com> wrote:
> >>
> >> Some platforms can't resume from d3cold state, So add a
> >> new module parameter to disable d3cold state for debugging
> >> purpose or workaround.
> >
> > Doesn't the runpm parameter already handle this?  If you set runpm=0,
> > that should disable d3cold.
> >
> runpm=0  prevents calls to driver runtime_suspend/resume functions.
> While d3cold=0 allows calls to runtime_suspend/resume functions and puts
> the device in d3hot state instead of d3cold.

But d3hot doesn't actually power down the card so it won't save any
power.  If we want to disable d3cold and still use runtime pm, it's
better to try and use BACO.

Alex

>
> Regards,
> Ma Jun
>
> > Alex
> >
> >>
> >> Signed-off-by: Ma Jun <Jun.Ma2 at amd.com>
> >> ---
> >>  drivers/gpu/drm/amd/amdgpu/amdgpu.h        | 1 +
> >>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 7 +++++++
> >>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    | 8 ++++++++
> >>  3 files changed, 16 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> index a9f54df9d33e..db9f60790267 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> @@ -166,6 +166,7 @@ extern char amdgpu_lockup_timeout[AMDGPU_MAX_TIMEOUT_PARAM_LENGTH];
> >>  extern int amdgpu_dpm;
> >>  extern int amdgpu_fw_load_type;
> >>  extern int amdgpu_aspm;
> >> +extern int amdgpu_d3cold;
> >>  extern int amdgpu_runtime_pm;
> >>  extern uint amdgpu_ip_block_mask;
> >>  extern int amdgpu_bapm;
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> index 22b6a910b7f2..90501c44e7d0 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> @@ -264,6 +264,13 @@ bool amdgpu_device_supports_px(struct drm_device *dev)
> >>  bool amdgpu_device_supports_boco(struct drm_device *dev)
> >>  {
> >>         struct amdgpu_device *adev = drm_to_adev(dev);
> >> +       struct pci_dev *parent;
> >> +
> >> +       if (!amdgpu_d3cold) {
> >> +               parent = pcie_find_root_port(adev->pdev);
> >> +               pci_d3cold_disable(parent);
> >> +               return false;
> >> +       }
> >>
> >>         if (adev->has_pr3 ||
> >>             ((adev->flags & AMD_IS_PX) && amdgpu_is_atpx_hybrid()))
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >> index 5f14f04cb553..c9fbb8bd4169 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> >> @@ -145,6 +145,7 @@ char amdgpu_lockup_timeout[AMDGPU_MAX_TIMEOUT_PARAM_LENGTH];
> >>  int amdgpu_dpm = -1;
> >>  int amdgpu_fw_load_type = -1;
> >>  int amdgpu_aspm = -1;
> >> +int amdgpu_d3cold = -1;
> >>  int amdgpu_runtime_pm = -1;
> >>  uint amdgpu_ip_block_mask = 0xffffffff;
> >>  int amdgpu_bapm = -1;
> >> @@ -359,6 +360,13 @@ module_param_named(fw_load_type, amdgpu_fw_load_type, int, 0444);
> >>  MODULE_PARM_DESC(aspm, "ASPM support (1 = enable, 0 = disable, -1 = auto)");
> >>  module_param_named(aspm, amdgpu_aspm, int, 0444);
> >>
> >> +/**
> >> + * DOC: d3cold (int)
> >> + * To disable d3cold (1 = enable, 0 = disable). The default is -1 (auto, enabled).
> >> + */
> >> +MODULE_PARM_DESC(d3cold, "d3cold support (1 = enable, 0 = disable, -1 = auto)");
> >> +module_param_named(d3cold, amdgpu_d3cold, int, 0444);
> >> +
> >>  /**
> >>   * DOC: runpm (int)
> >>   * Override for runtime power management control for dGPUs. The amdgpu driver can dynamically power down
> >> --
> >> 2.34.1
> >>