| Message ID | 20190307103454.1637485-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | drm/amd/display: avoid passing enum as NULL pointer | expand |
On Thu, Mar 07, 2019 at 11:34:29AM +0100, Arnd Bergmann wrote: > The mod_freesync_build_vrr_infopacket() function uses rather obscure > calling conventions, where an enum is passed in through a pointer, > and a NULL pointer is expected to behave the same way as the zero-value > (TRANSFER_FUNC_UNKNOWN). > > Trying to build this with clang results in a warning: > > drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4601:3: error: expression which evaluates to zero treated > as a null pointer constant of type 'const enum color_transfer_func *' [-Werror,-Wnon-literal-null-conversion] > > Passing it by value instead of by reference makes the code simpler > and more conventional but should not change the behavior at all. > > Fixes: c2791297013e ("drm/amd/display: Add color bit info to freesync infoframe") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > 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 94a84bc57c7a..6f32fe129880 100644 > --- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c > +++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c > @@ -724,7 +724,7 @@ 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, > + const enum color_transfer_func app_tf, > struct dc_info_packet *infopacket) > { > unsigned int payload_size = 0; > @@ -732,8 +732,7 @@ 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); > > @@ -757,7 +756,7 @@ 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, > + const 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 4222e403b151..645793b924cf 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, > + const enum color_transfer_func app_tf, > struct dc_info_packet *infopacket); > > void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync, > -- > 2.20.0 > Just as an FYI, I sent the same fix when the warning first hit which was recently accepted: https://cgit.freedesktop.org/~agd5f/linux/commit/?id=672e78cab819ebe31e3b9b8abac367be8a110472 Just waiting for it to hit mainline. Cheers, Nathan
diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c index 94a84bc57c7a..6f32fe129880 100644 --- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c +++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c @@ -724,7 +724,7 @@ 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, + const enum color_transfer_func app_tf, struct dc_info_packet *infopacket) { unsigned int payload_size = 0; @@ -732,8 +732,7 @@ 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); @@ -757,7 +756,7 @@ 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, + const 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 4222e403b151..645793b924cf 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, + const enum color_transfer_func app_tf, struct dc_info_packet *infopacket); void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
The mod_freesync_build_vrr_infopacket() function uses rather obscure calling conventions, where an enum is passed in through a pointer, and a NULL pointer is expected to behave the same way as the zero-value (TRANSFER_FUNC_UNKNOWN). Trying to build this with clang results in a warning: drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:4601:3: error: expression which evaluates to zero treated as a null pointer constant of type 'const enum color_transfer_func *' [-Werror,-Wnon-literal-null-conversion] Passing it by value instead of by reference makes the code simpler and more conventional but should not change the behavior at all. Fixes: c2791297013e ("drm/amd/display: Add color bit info to freesync infoframe") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- 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(-) -- 2.20.0