[PATCH 1/6] drm/amdgpu/gfx6: fix CSIB handling

[Rodrigo Siqueira]

On 03/25, Alex Deucher wrote:
> On Tue, Mar 25, 2025 at 4:16 PM Rodrigo Siqueira <siqueira at igalia.com> wrote:
> >
> > On 03/19, Alex Deucher wrote:
> > > We shouldn't return after the last section.
> > > We need to update the rest of the CSIB.
> >
> > What is CSIB?
> 
> Clear State Indirect Buffer.  It provides the clear state that gets
> put into the hardware context if when user mode puts requests the
> clear state in their command buffer.  Driver programs this explicitly
> when it sets up the kernel rings.  Driver also provides a pointer to
> it which is used by the firmware to load the clear state in some
> cases.
>

Thanks for the explanation.
 
> >
> > What happens if the other CSIB is not updated?
> 
> The clear state packet submitted by userspace won't work as expected
> if the clear state is not properly initialized.  In this case, I'm not
> sure if there is actually a function difference since the driver
> always initializes the clear state at kernel queue init time, but best
> to make sure the buffer pointed to by the RLC is correct.
>

Make sense.

This series is:

Reviewed-by: Rodrigo Siqueira <siqueira at igalia.com>

Thanks
 
> Alex
> 
> >
> > Thanks
> >
> > >
> > > Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> > > ---
> > >  drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c | 2 --
> > >  1 file changed, 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> > > index 13fbee46417af..cee2cf47112c9 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> > > @@ -2874,8 +2874,6 @@ static void gfx_v6_0_get_csb_buffer(struct amdgpu_device *adev,
> > >                               buffer[count++] = cpu_to_le32(ext->reg_index - 0xa000);
> > >                               for (i = 0; i < ext->reg_count; i++)
> > >                                       buffer[count++] = cpu_to_le32(ext->extent[i]);
> > > -                     } else {
> > > -                             return;
> > >                       }
> > >               }
> > >       }
> > > --
> > > 2.48.1
> > >
> >
> > --
> > Rodrigo Siqueira

-- 
Rodrigo Siqueira