From: Ivan Lipski <ivlipski@xxxxxxx> [WHY] Coverity analysis of the Upstream display driver code (amd-staging-drm-next) flagged these three functions as containing 'CONSTANT_EXPRESSION_RESULT' errors, i. e. the conditionals are reduntant since their result is predetermined. fixpt31_32.c: The two flagged 'ASSERT' lines redundant since they are always true: - LONG_MAX equals to the largest 'signed long long' number - res.value is type 'signed long long', So, the condition inside the 'ASSERTS's is always link_dp_training.c: The flagged conditional statement is always false: - 'max_requested.FFE_PRESET.settings.level' is 4 bits, so its max possible value is 15 - 'DP_FFE_PRESET_MAX_LEVEL' equals to 15. So, the conditional statement is always false and the wrapped code never executes. [HOW] Removed lines flagged by Coverity analysis. Reviewed-by: Sun peng Li <sunpeng.li@xxxxxxx> Acked-by: Zaeem Mohamed <zaeem.mohamed@xxxxxxx> Signed-off-by: Ivan Lipski <ivlipski@xxxxxxx> --- drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c | 4 ---- .../drm/amd/display/dc/link/protocols/link_dp_training.c | 8 ++++++-- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c b/drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c index 1726bdf89bae..506f82cd5cc6 100644 --- a/drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c +++ b/drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c @@ -140,8 +140,6 @@ struct fixed31_32 dc_fixpt_mul(struct fixed31_32 arg1, struct fixed31_32 arg2) res.value = arg1_int * arg2_int; - ASSERT(res.value <= LONG_MAX); - res.value <<= FIXED31_32_BITS_PER_FRACTIONAL_PART; tmp = arg1_int * arg2_fra; @@ -185,8 +183,6 @@ struct fixed31_32 dc_fixpt_sqr(struct fixed31_32 arg) res.value = arg_int * arg_int; - ASSERT(res.value <= LONG_MAX); - res.value <<= FIXED31_32_BITS_PER_FRACTIONAL_PART; tmp = arg_int * arg_fra; diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c index a93dd83cd8c0..5a0f574056d4 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c @@ -329,8 +329,12 @@ static void maximize_lane_settings(const struct link_training_settings *lt_setti if (max_requested.PRE_EMPHASIS > PRE_EMPHASIS_MAX_LEVEL) max_requested.PRE_EMPHASIS = PRE_EMPHASIS_MAX_LEVEL; - if (max_requested.FFE_PRESET.settings.level > DP_FFE_PRESET_MAX_LEVEL) - max_requested.FFE_PRESET.settings.level = DP_FFE_PRESET_MAX_LEVEL; + + /* Note, we are not checking + * if max_requested.FFE_PRESET.settings.level > DP_FFE_PRESET_MAX_LEVEL, + * since FFE_PRESET.settings.level is 4 bits and DP_FFE_PRESET_MAX_LEVEL equals 15, + * so FFE_PRESET.settings.level will never be greater than 15. + */ /* make sure the pre-emphasis matches the voltage swing*/ if (max_requested.PRE_EMPHASIS > -- 2.34.1
