Re: [PATCH] gpu: drm: amd: amdgpu: remove dead code

[Alex Deucher]

On Mon, May 8, 2017 at 1:01 PM, Gustavo A. R. Silva
<garsilva@xxxxxxxxxxxxxx> wrote:
> Local variable use_doorbell is assigned to a constant value and it is never
> updated again. Remove this variable and the dead code it guards.
>
> Addresses-Coverity-ID: 1401828
> Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>

This code is already removed in the latest code queued for the next
kernel for gfx8.  For gfx7, I think Andres' priority patch set fixes
this up for gfx7.

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c | 53 +++++++++++++----------------------
>  1 file changed, 20 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> index 67afc90..e824c2b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> @@ -4991,7 +4991,6 @@ static int gfx_v8_0_cp_compute_resume(struct amdgpu_device *adev)
>  {
>         int r, i, j;
>         u32 tmp;
> -       bool use_doorbell = true;
>         u64 hqd_gpu_addr;
>         u64 mqd_gpu_addr;
>         u64 eop_gpu_addr;
> @@ -5079,11 +5078,7 @@ static int gfx_v8_0_cp_compute_resume(struct amdgpu_device *adev)
>
>                 /* enable doorbell? */
>                 tmp = RREG32(mmCP_HQD_PQ_DOORBELL_CONTROL);
> -               if (use_doorbell) {
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_EN, 1);
> -               } else {
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_EN, 0);
> -               }
> +               tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_EN, 1);
>                 WREG32(mmCP_HQD_PQ_DOORBELL_CONTROL, tmp);
>                 mqd->cp_hqd_pq_doorbell_control = tmp;
>
> @@ -5157,29 +5152,23 @@ static int gfx_v8_0_cp_compute_resume(struct amdgpu_device *adev)
>                        mqd->cp_hqd_pq_wptr_poll_addr_hi);
>
>                 /* enable the doorbell if requested */
> -               if (use_doorbell) {
> -                       if ((adev->asic_type == CHIP_CARRIZO) ||
> -                           (adev->asic_type == CHIP_FIJI) ||
> -                           (adev->asic_type == CHIP_STONEY) ||
> -                           (adev->asic_type == CHIP_POLARIS11) ||
> -                           (adev->asic_type == CHIP_POLARIS10) ||
> -                           (adev->asic_type == CHIP_POLARIS12)) {
> -                               WREG32(mmCP_MEC_DOORBELL_RANGE_LOWER,
> -                                      AMDGPU_DOORBELL_KIQ << 2);
> -                               WREG32(mmCP_MEC_DOORBELL_RANGE_UPPER,
> -                                      AMDGPU_DOORBELL_MEC_RING7 << 2);
> -                       }
> -                       tmp = RREG32(mmCP_HQD_PQ_DOORBELL_CONTROL);
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL,
> -                                           DOORBELL_OFFSET, ring->doorbell_index);
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_EN, 1);
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_SOURCE, 0);
> -                       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_HIT, 0);
> -                       mqd->cp_hqd_pq_doorbell_control = tmp;
> -
> -               } else {
> -                       mqd->cp_hqd_pq_doorbell_control = 0;
> +               if ((adev->asic_type == CHIP_CARRIZO) ||
> +                   (adev->asic_type == CHIP_FIJI) ||
> +                   (adev->asic_type == CHIP_STONEY) ||
> +                   (adev->asic_type == CHIP_POLARIS11) ||
> +                   (adev->asic_type == CHIP_POLARIS10) ||
> +                   (adev->asic_type == CHIP_POLARIS12)) {
> +                       WREG32(mmCP_MEC_DOORBELL_RANGE_LOWER, AMDGPU_DOORBELL_KIQ << 2);
> +                       WREG32(mmCP_MEC_DOORBELL_RANGE_UPPER, AMDGPU_DOORBELL_MEC_RING7 << 2);
>                 }
> +               tmp = RREG32(mmCP_HQD_PQ_DOORBELL_CONTROL);
> +               tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL,
> +                                  DOORBELL_OFFSET, ring->doorbell_index);
> +               tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_EN, 1);
> +               tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_SOURCE, 0);
> +               tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_DOORBELL_CONTROL, DOORBELL_HIT, 0);
> +               mqd->cp_hqd_pq_doorbell_control = tmp;
> +
>                 WREG32(mmCP_HQD_PQ_DOORBELL_CONTROL,
>                        mqd->cp_hqd_pq_doorbell_control);
>
> @@ -5217,11 +5206,9 @@ static int gfx_v8_0_cp_compute_resume(struct amdgpu_device *adev)
>                 amdgpu_bo_unreserve(ring->mqd_obj);
>         }
>
> -       if (use_doorbell) {
> -               tmp = RREG32(mmCP_PQ_STATUS);
> -               tmp = REG_SET_FIELD(tmp, CP_PQ_STATUS, DOORBELL_ENABLE, 1);
> -               WREG32(mmCP_PQ_STATUS, tmp);
> -       }
> +       tmp = RREG32(mmCP_PQ_STATUS);
> +       tmp = REG_SET_FIELD(tmp, CP_PQ_STATUS, DOORBELL_ENABLE, 1);
> +       WREG32(mmCP_PQ_STATUS, tmp);
>
>         gfx_v8_0_cp_compute_enable(adev, true);
>
> --
> 2.5.0
>
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