From: Nathan Chancellor natechancellor@gmail.com
[ Upstream commit 672e78cab819ebe31e3b9b8abac367be8a110472 ]
Clang warns when an expression that equals zero is used as a null pointer constant (in lieu of NULL):
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4435:3: warning: expression which evaluates to zero treated as a null pointer constant of type 'const enum color_transfer_func *' [-Wnon-literal-null-conversion] TRANSFER_FUNC_UNKNOWN, ^~~~~~~~~~~~~~~~~~~~~ 1 warning generated.
This warning is caused by commit bb47de736661 ("drm/amdgpu: Set FreeSync state using drm VRR properties") and it could be solved by using NULL instead of TRANSFER_FUNC_UNKNOWN or casting TRANSFER_FUNC_UNKNOWN as a pointer. However, after looking into it, there doesn't appear to be a good reason to pass app_tf by reference as it is never mutated along the way. This is the only code path in which app_tf is used:
mod_freesync_build_vrr_infopacket -> build_vrr_infopacket_v2 -> build_vrr_infopacket_fs2_data
Neither mod_freesync_build_vrr_infopacket or build_vrr_infopacket_v2 modify app_tf's value and build_vrr_infopacket_fs2_data expects just the value so we can avoid dereferencing anything by just passing in app_tf's value to mod_freesync_build_vrr_infopacket and build_vrr_infopacket_v2.
There is no functional change because build_vrr_infopacket_fs2_data doesn't do anything if TRANSFER_FUNC_UNKNOWN is passed to it, the same as not calling build_vrr_infopacket_fs2_data at all like before this change when NULL was used for app_tf.
Reviewed-by: Harry Wentland harry.wentland@amd.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/display/modules/freesync/freesync.c | 7 +++---- drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c index 1544ed3f1747..945e845f3358 100644 --- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c +++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c @@ -656,7 +656,7 @@ static void build_vrr_infopacket_v1(enum signal_type signal,
static void build_vrr_infopacket_v2(enum signal_type signal, const struct mod_vrr_params *vrr, - const enum color_transfer_func *app_tf, + enum color_transfer_func app_tf, struct dc_info_packet *infopacket) { unsigned int payload_size = 0; @@ -664,8 +664,7 @@ static void build_vrr_infopacket_v2(enum signal_type signal, build_vrr_infopacket_header_v2(signal, infopacket, &payload_size); build_vrr_infopacket_data(vrr, infopacket);
- if (app_tf != NULL) - build_vrr_infopacket_fs2_data(*app_tf, infopacket); + build_vrr_infopacket_fs2_data(app_tf, infopacket);
build_vrr_infopacket_checksum(&payload_size, infopacket);
@@ -676,7 +675,7 @@ void mod_freesync_build_vrr_infopacket(struct mod_freesync *mod_freesync, const struct dc_stream_state *stream, const struct mod_vrr_params *vrr, enum vrr_packet_type packet_type, - const enum color_transfer_func *app_tf, + enum color_transfer_func app_tf, struct dc_info_packet *infopacket) { /* SPD info packet for FreeSync */ diff --git a/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h b/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h index 949a8b62aa98..063af6258fd9 100644 --- a/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h +++ b/drivers/gpu/drm/amd/display/modules/inc/mod_freesync.h @@ -145,7 +145,7 @@ void mod_freesync_build_vrr_infopacket(struct mod_freesync *mod_freesync, const struct dc_stream_state *stream, const struct mod_vrr_params *vrr, enum vrr_packet_type packet_type, - const enum color_transfer_func *app_tf, + enum color_transfer_func app_tf, struct dc_info_packet *infopacket);
void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,