From: Dan Carpenter Date: Fri, 31 Oct 2025 13:02:25 +0000 (+0300) Subject: drm/amd/display: Fix logical vs bitwise bug in get_embedded_panel_info_v2_1() X-Git-Url: https://gentwo.org/gitweb/?a=commitdiff_plain;h=1a79482699b4d1e43948d14f0c7193dc1dcad858;p=linux%2F.git drm/amd/display: Fix logical vs bitwise bug in get_embedded_panel_info_v2_1() The .H_SYNC_POLARITY and .V_SYNC_POLARITY variables are 1 bit bitfields of a u32. The ATOM_HSYNC_POLARITY define is 0x2 and the ATOM_VSYNC_POLARITY is 0x4. When we do a bitwise negate of 0, 2, or 4 then the last bit is always 1 so this code always sets .H_SYNC_POLARITY and .V_SYNC_POLARITY to true. This code is instead intended to check if the ATOM_HSYNC_POLARITY or ATOM_VSYNC_POLARITY flags are set and reverse the result. In other words, it's supposed to be a logical negate instead of a bitwise negate. Fixes: ae79c310b1a6 ("drm/amd/display: Add DCE12 bios parser support") Signed-off-by: Dan Carpenter Reviewed-by: Alex Hung Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c b/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c index 04eb647acc4e..550a9f1d03f8 100644 --- a/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c +++ b/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c @@ -1480,10 +1480,10 @@ static enum bp_result get_embedded_panel_info_v2_1( /* not provided by VBIOS */ info->lcd_timing.misc_info.HORIZONTAL_CUT_OFF = 0; - info->lcd_timing.misc_info.H_SYNC_POLARITY = ~(uint32_t) (lvds->lcd_timing.miscinfo - & ATOM_HSYNC_POLARITY); - info->lcd_timing.misc_info.V_SYNC_POLARITY = ~(uint32_t) (lvds->lcd_timing.miscinfo - & ATOM_VSYNC_POLARITY); + info->lcd_timing.misc_info.H_SYNC_POLARITY = !(lvds->lcd_timing.miscinfo & + ATOM_HSYNC_POLARITY); + info->lcd_timing.misc_info.V_SYNC_POLARITY = !(lvds->lcd_timing.miscinfo & + ATOM_VSYNC_POLARITY); /* not provided by VBIOS */ info->lcd_timing.misc_info.VERTICAL_CUT_OFF = 0;