[PATCH] drm/amdgpu: Check if smu.ppt_funcs is initialized before accessing

[Huang, Ray]

> -----Original Message-----
> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf
> Of Alex Deucher
> Sent: Friday, April 19, 2019 10:26 PM
> To: Li, Sun peng (Leo) <Sunpeng.Li at amd.com>
> Cc: Gui, Jack <Jack.Gui at amd.com>; amd-gfx list <amd-
> gfx at lists.freedesktop.org>
> Subject: Re: [PATCH] drm/amdgpu: Check if smu.ppt_funcs is initialized
> before accessing
> 
> On Thu, Apr 18, 2019 at 12:01 PM <sunpeng.li at amd.com> wrote:
> >
> > From: Leo Li <sunpeng.li at amd.com>
> >
> > smu.ppt_funcs is only initialized for specific SMU versions.
> >
> > On a Hawaii ASIC, attempting to access the udev attribute
> > ATTRS{power_dpm_state} will cause a null pointer deref in
> > amdgpu_get_dpm_state() because of this.
> >
> > Fix by checking that ppt_funcs is initialized first.
> >
> > CC: Chengming Gui <Jack.Gui at amd.com>
> > Signed-off-by: Leo Li <sunpeng.li at amd.com>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> > index 4b7a076..7993623 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> > @@ -144,7 +144,7 @@ static ssize_t amdgpu_get_dpm_state(struct device
> *dev,
> >         struct amdgpu_device *adev = ddev->dev_private;
> >         enum amd_pm_state_type pm;
> >
> > -       if (adev->smu.ppt_funcs->get_current_power_state)
> > +       if (adev->smu.ppt_funcs && adev->smu.ppt_funcs-
> >get_current_power_state)
> 
> For consistency, I think we probably want something like:
> if (is_support_sw_smu(adev) && adev->smu.ppt_funcs-
> >get_current_power_state)
> 
> Either way:
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

Yes. The same comment with me. Please use is_support_sw_smu() to check it.
With that fixed, please add Reviewed-by: Huang Rui <ray.huang at amd.com>

> 
> >                 pm = amdgpu_smu_get_current_power_state(adev);
> >         else if (adev->powerplay.pp_funcs->get_current_power_state)
> >                 pm = amdgpu_dpm_get_current_power_state(adev);
> > --
> > 2.7.4
> >
> > _______________________________________________
> > amd-gfx mailing list
> > amd-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
> _______________________________________________
> amd-gfx mailing list
> amd-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx