linux-kernel - [PATCH] drm/amd/display: Simplify condition in try_disable

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Date:   Mon, 21 Sep 2020 22:47:43 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] drm/amd/display: Simplify condition in try_disable_dsc

Clang warns:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:637:8:
warning: logical not is only applied to the left hand side of this
comparison [-Wlogical-not-parentheses]
                                && !params[i].clock_force_enable == DSC_CLK_FORCE_DEFAULT) {
                                   ^                             ~~
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:637:8:
note: add parentheses after the '!' to evaluate the comparison first
                                && !params[i].clock_force_enable == DSC_CLK_FORCE_DEFAULT) {
                                   ^
                                    (
)
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_mst_types.c:637:8:
note: add parentheses around left hand side expression to silence this
warning
                                && !params[i].clock_force_enable == DSC_CLK_FORCE_DEFAULT) {
                                   ^
                                   (                            )
1 warning generated.

The expression "!a == 0" can be more simply written as "a", which makes
it easier to reason about the logic and prevents the warning.

Fixes: 0749ddeb7d6c ("drm/amd/display: Add DSC force disable to dsc_clock_en debugfs entry")
Link: https://github.com/ClangBuiltLinux/linux/issues/1158
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 9d7333a36fac..0852a24ee392 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -634,7 +634,7 @@ static void try_disable_dsc(struct drm_atomic_state *state,
 	for (i = 0; i < count; i++) {
 		if (vars[i].dsc_enabled
 				&& vars[i].bpp_x16 == params[i].bw_range.max_target_bpp_x16
-				&& !params[i].clock_force_enable == DSC_CLK_FORCE_DEFAULT) {
+				&& params[i].clock_force_enable) {
 			kbps_increase[i] = params[i].bw_range.stream_kbps - params[i].bw_range.max_kbps;
 			tried[i] = false;
 			remaining_to_try += 1;

base-commit: 6651cdf3bfeeaeb499db11668313666bf756579a
-- 
2.28.0