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From e9bc7091b5cf10a59998a4b13cd34841cd105ec4 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <natechancellor@gmail.com>
Date: Tue, 19 Mar 2019 17:58:42 -0700
Subject: [PATCH 1659/2940] drm/amd/powerplay: Zero initialize num_of_levels in
vega20_set_single_dpm_table
When building with -Wsometimes-uninitialized, Clang warns:
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: warning:
variable 'num_of_levels' is used uninitialized whenever '?:' condition
is false [-Wsometimes-uninitialized]
smu_read_smc_arg(smu, &num_of_levels);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:457:7: note:
uninitialized use occurs here
if (!num_of_levels) {
^~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:456:2: note: remove
the '?:' if its condition is always true
smu_read_smc_arg(smu, &num_of_levels);
^
drivers/gpu/drm/amd/amdgpu/../powerplay/inc/amdgpu_smu.h:608:3: note:
expanded from macro 'smu_read_smc_arg'
((smu)->funcs->read_smc_arg? (smu)->funcs->read_smc_arg((smu), (arg)) : 0)
^
drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:446:27: note:
initialize the variable 'num_of_levels' to silence this warning
uint32_t i, num_of_levels, clk;
^
= 0
1 warning generated.
The if statement it mentions as potentially problematic is currently
always true because the read_smc_arg callback is assigned at the
bottom of this file but Clang can't tell that. If the callback were
ever to disappear, num_of_levels would never be initialized. Just
zero initialize it to ensure that the intent behind this code
remains the same.
Fixes: 870b996f955f ("drm/amd/powerplay: set defalut dpm table for smu")
Link: https://github.com/ClangBuiltLinux/linux/issues/425
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
drivers/gpu/drm/amd/powerplay/vega20_ppt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
index 5b4adf901fae..5297b23ebcd1 100644
--- a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
+++ b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
@@ -443,7 +443,7 @@ vega20_set_single_dpm_table(struct smu_context *smu,
PPCLK_e clk_id)
{
int ret = 0;
- uint32_t i, num_of_levels, clk;
+ uint32_t i, num_of_levels = 0, clk;
ret = smu_send_smc_msg_with_param(smu,
SMU_MSG_GetDpmFreqByIndex,
--
2.17.1
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