[PATCH] drm/amdgpu: disable cstate properly for driver reloading scenario

[Quan, Evan]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Lazar, Lijo <Lijo.Lazar at amd.com>
> Sent: Thursday, March 2, 2023 4:28 PM
> To: Quan, Evan <Evan.Quan at amd.com>; amd-gfx at lists.freedesktop.org
> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>
> Subject: Re: [PATCH] drm/amdgpu: disable cstate properly for driver
> reloading scenario
> 
> 
> 
> On 3/2/2023 12:28 PM, Evan Quan wrote:
> > Gpu reset might be needed during driver reloading. To guard that(gpu
> > reset) work, df cstate needs to be disabled properly.
> >
> > Signed-off-by: Evan Quan <evan.quan at amd.com>
> > Change-Id: I5c074c265c0b08a67b6934ae1ad9aa3fed245461
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > index 51bbeaa1f311..3c854461ef32 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > @@ -2816,6 +2816,15 @@ static int amdgpu_device_ip_fini_early(struct
> amdgpu_device *adev)
> >   	amdgpu_device_set_pg_state(adev, AMD_PG_STATE_UNGATE);
> >   	amdgpu_device_set_cg_state(adev, AMD_CG_STATE_UNGATE);
> >
> > +	/*
> > +	 * Get df cstate disabled properly on driver unloading.
> > +	 * Since on the succeeding driver reloading, gpu reset might
> > +	 * be required. And cstate disabled is a prerequisite for
> > +	 * that(gpu reset).
> > +	 */
> > +	if (amdgpu_dpm_set_df_cstate(adev, DF_CSTATE_DISALLOW))
> > +		dev_warn(adev->dev, "Failed to disallow df cstate");
> > +
> 
> This looks more like a firmware bug. Driver sends the Unload message to FW.
> In that case FW should disable all features including C-state.
Driver does not send the Unload message. We want PMFM alive and ready for handling possible gpu reset on reloading.

BR
Evan
> 
> Thanks,
> Lijo
> 
> >   	amdgpu_amdkfd_suspend(adev, false);
> >
> >   	/* Workaroud for ASICs need to disable SMC first */