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From 6c13d7d3ba65090b6817972126a06f380f8e20b8 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <natechancellor@gmail.com>
Date: Sat, 23 Nov 2019 12:23:36 -0700
Subject: [PATCH 4595/4736] drm/amdgpu: Ensure ret is always initialized when
using SOC15_WAIT_ON_RREG
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@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
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; \
--
2.17.1
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