From 0228687423587d8ef448fc1d81f96539507aa5bb Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Wed, 23 Apr 2025 10:41:41 -0700 Subject: [PATCH] drm/panel: himax-hx8279: Always initialize goa_{even,odd}_valid in hx8279_check_goa_config() Clang warns (or errors with CONFIG_WERROR=y): drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here 842 | if (goa_odd_valid != goa_even_valid) | ^~~~~~~~~~~~~~ drivers/gpu/drm/panel/panel-himax-hx8279.c:838:2: note: remove the 'if' if its condition is always true 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing)) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 839 | goa_even_valid = false; drivers/gpu/drm/panel/panel-himax-hx8279.c:818:36: note: initialize the variable 'goa_even_valid' to silence this warning 818 | bool goa_odd_valid, goa_even_valid; | ^ | = 0 Even though only the even valid variable gets flagged, both valid variables appear to have the same issue of possibly being used uninitialized if the if statement initializing them to false is not taken. Turn the if statement then variable assignment into a single variable assignment, which states that the configuration is valid when there are not all zeros, clearing up the warning since the variable will always be initialized. Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels") Suggested-by: AngeloGioacchino Del Regno Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Nathan Chancellor Reviewed-by: Neil Armstrong Link: https://lore.kernel.org/r/20250423-panel-himax-hx8279-fix-sometimes-uninitialized-v2-1-fc501c6558d9@kernel.org Signed-off-by: Neil Armstrong Link: https://lore.kernel.org/r/20250423-panel-himax-hx8279-fix-sometimes-uninitialized-v2-1-fc501c6558d9@kernel.org --- drivers/gpu/drm/panel/panel-himax-hx8279.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/panel/panel-himax-hx8279.c b/drivers/gpu/drm/panel/panel-himax-hx8279.c index b48b350b62da..fb302d1f91b9 100644 --- a/drivers/gpu/drm/panel/panel-himax-hx8279.c +++ b/drivers/gpu/drm/panel/panel-himax-hx8279.c @@ -825,8 +825,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev) num_zero++; } - if (num_zero == ARRAY_SIZE(desc->goa_odd_timing)) - goa_odd_valid = false; + goa_odd_valid = (num_zero != ARRAY_SIZE(desc->goa_odd_timing)); /* Up to 3 zeroes is a valid config. Check them all. */ num_zero = 1; @@ -835,8 +834,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev) num_zero++; } - if (num_zero == ARRAY_SIZE(desc->goa_even_timing)) - goa_even_valid = false; + goa_even_valid = (num_zero != ARRAY_SIZE(desc->goa_even_timing)); /* Programming one without the other would make no sense! */ if (goa_odd_valid != goa_even_valid) -- 2.50.1