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From:   Nathan Chancellor <nathan@kernel.org>
To:     Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH] drm/amd: Initialize remove_mpcc in dcn201_update_mpcc()
Date:   Thu, 30 Sep 2021 09:16:42 -0700
Message-Id: <20210930161641.2333583-1-nathan@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Clang warns:

drivers/gpu/drm/amd/amdgpu/../display/dc/dcn201/dcn201_hwseq.c:505:6: error: variable 'remove_mpcc' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        if (mpc->funcs->get_mpcc_for_dpp_from_secondary)
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn201/dcn201_hwseq.c:509:6: note: uninitialized use occurs here
        if (remove_mpcc != NULL && mpc->funcs->remove_mpcc_from_secondary)
            ^~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn201/dcn201_hwseq.c:505:2: note: remove the 'if' if its condition is always true
        if (mpc->funcs->get_mpcc_for_dpp_from_secondary)
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn201/dcn201_hwseq.c:442:26: note: initialize the variable 'remove_mpcc' to silence this warning
        struct mpcc *remove_mpcc;
                                ^
                                 = NULL
1 error generated.

The code already handles remove_mpcc being NULL just fine so initialize
it to NULL at the beginning of the function so it is never used
uninitialized.

Fixes: ff7e396f822f ("drm/amd/display: add cyan_skillfish display support")
Link: https://github.com/ClangBuiltLinux/linux/issues/1469
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
index ceaaeeb8f2de..cfd09b3f705e 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hwseq.c
@@ -439,7 +439,7 @@ void dcn201_update_mpcc(struct dc *dc, struct pipe_ctx *pipe_ctx)
 	bool per_pixel_alpha = pipe_ctx->plane_state->per_pixel_alpha && pipe_ctx->bottom_pipe;
 	int mpcc_id, dpp_id;
 	struct mpcc *new_mpcc;
-	struct mpcc *remove_mpcc;
+	struct mpcc *remove_mpcc = NULL;
 	struct mpc *mpc = dc->res_pool->mpc;
 	struct mpc_tree *mpc_tree_params = &(pipe_ctx->stream_res.opp->mpc_tree_params);
 

base-commit: 30fc33064c846df29888c3c61e30a064aad3a342
-- 
2.33.0.591.gddb1055343