From a882dcd9fd487eca8f019dd9814cacb7fb82b2c4 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Sat, 23 Nov 2019 12:23:36 -0700 Subject: [PATCH] drm/amdgpu: Ensure ret is always initialized when using SOC15_WAIT_ON_RREG [ Upstream commit a63141e31764f8daf3f29e8e2d450dcf9199d1c8 ] 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 Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- 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 0942f492d2e1..9d444f7fdfcd 100644 --- a/drivers/gpu/drm/amd/amdgpu/soc15_common.h +++ b/drivers/gpu/drm/amd/amdgpu/soc15_common.h @@ -51,6 +51,7 @@ do { \ 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)) { \ udelay(2); \ tmp_ = RREG32(adev->reg_offset[ip##_HWIP][inst][reg##_BASE_IDX] + reg); \