On Mon, Nov 25, 2019 at 3:07 AM Nathan Chancellor
<natechancellor@xxxxxxxxx> wrote:
>
> Commit b0f3cd3191cd ("drm/amdgpu: remove unnecessary JPEG2.0 code from
> VCN2.0") introduced a new clang warning in the vcn_v2_0_stop function:
>
> ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1082:2: warning: variable 'r'
> is used uninitialized whenever 'while' loop exits because its condition
> is false [-Wsometimes-uninitialized]
> SOC15_WAIT_ON_RREG(VCN, 0, mmUVD_STATUS, UVD_STATUS__IDLE, 0x7, r);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/gpu/drm/amd/amdgpu/../amdgpu/soc15_common.h:55:10: note:
> expanded from macro 'SOC15_WAIT_ON_RREG'
> while ((tmp_ & (mask)) != (expected_value)) { \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1083:6: note: uninitialized use
> occurs here
> if (r)
> ^
> ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1082:2: note: remove the
> condition if it is always true
> SOC15_WAIT_ON_RREG(VCN, 0, mmUVD_STATUS, UVD_STATUS__IDLE, 0x7, r);
> ^
> ../drivers/gpu/drm/amd/amdgpu/../amdgpu/soc15_common.h:55:10: note:
> expanded from macro 'SOC15_WAIT_ON_RREG'
> while ((tmp_ & (mask)) != (expected_value)) { \
> ^
> ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1072:7: note: initialize the
> variable 'r' to silence this warning
> int r;
> ^
> = 0
> 1 warning generated.
>
> To prevent warnings like this from happening in the future, make the
> SOC15_WAIT_ON_RREG macro initialize its ret variable before the while
> loop that can time out. This macro's return value is always checked so
> it should set ret in both the success and fail path.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/776
> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Applied. Thanks!
Alex
> ---
> drivers/gpu/drm/amd/amdgpu/soc15_common.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/soc15_common.h b/drivers/gpu/drm/amd/amdgpu/soc15_common.h
> index 839f186e1182..19e870c79896 100644
> --- a/drivers/gpu/drm/amd/amdgpu/soc15_common.h
> +++ b/drivers/gpu/drm/amd/amdgpu/soc15_common.h
> @@ -52,6 +52,7 @@
> uint32_t old_ = 0; \
> uint32_t tmp_ = RREG32(adev->reg_offset[ip##_HWIP][inst][reg##_BASE_IDX] + reg); \
> uint32_t loop = adev->usec_timeout; \
> + ret = 0; \
> while ((tmp_ & (mask)) != (expected_value)) { \
> if (old_ != tmp_) { \
> loop = adev->usec_timeout; \
> --
> 2.24.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
