This is a note to let you know that I've just added the patch titled drm/amd/display: fix overflow on MIN_I64 definition to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amd-display-fix-overflow-on-min_i64-definition.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2be7549049ddb476a5bac95fc4a939f00969aae1 Author: David Gow <davidgow@xxxxxxxxxx> Date: Thu Aug 11 17:43:26 2022 -0300 drm/amd/display: fix overflow on MIN_I64 definition [ Upstream commit 6ae0632d17759852c07e2d1e0a31c728eb6ba246 ] The definition of MIN_I64 in bw_fixed.c can cause gcc to whinge about integer overflow, because it is treated as a positive value, which is then negated. The temporary positive value is not necessarily representable. This causes the following warning: ../drivers/gpu/drm/amd/amdgpu/../display/dc/dml/calcs/bw_fixed.c:30:19: warning: integer overflow in expression ‘-9223372036854775808’ of type ‘long long int’ results in ‘-9223372036854775808’ [-Woverflow] 30 | (int64_t)(-(1LL << 63)) | ^ Writing out (-MAX_I64 - 1) works instead. Signed-off-by: David Gow <davidgow@xxxxxxxxxx> Signed-off-by: Tales Aparecida <tales.aparecida@xxxxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/display/dc/calcs/bw_fixed.c b/drivers/gpu/drm/amd/display/dc/calcs/bw_fixed.c index 6ca288fb5fb9..2d46bc527b21 100644 --- a/drivers/gpu/drm/amd/display/dc/calcs/bw_fixed.c +++ b/drivers/gpu/drm/amd/display/dc/calcs/bw_fixed.c @@ -26,12 +26,12 @@ #include "bw_fixed.h" -#define MIN_I64 \ - (int64_t)(-(1LL << 63)) - #define MAX_I64 \ (int64_t)((1ULL << 63) - 1) +#define MIN_I64 \ + (-MAX_I64 - 1) + #define FRACTIONAL_PART_MASK \ ((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)