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| author | Dan Carpenter <dan.carpenter@linaro.org> | 2025-10-31 16:02:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-12-18 13:55:09 +0100 |
| commit | 332825d72dcb3fcd57c9b7b06d902eda02932998 (patch) | |
| tree | 3a0f9c2e7ecc09c79df5b9627dcc3de6f9893d62 /drivers | |
| parent | 1b3eb9500fc558aa383915471bd85a35327b9786 (diff) | |
| download | linux-332825d72dcb3fcd57c9b7b06d902eda02932998.tar.gz linux-332825d72dcb3fcd57c9b7b06d902eda02932998.tar.bz2 linux-332825d72dcb3fcd57c9b7b06d902eda02932998.zip | |
drm/amd/display: Fix logical vs bitwise bug in get_embedded_panel_info_v2_1()
[ Upstream commit 1a79482699b4d1e43948d14f0c7193dc1dcad858 ]
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 <dan.carpenter@linaro.org>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c | 8 |
1 files changed, 4 insertions, 4 deletions
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 c9a6de110b74..af31fddb47db 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; |