| Message ID | 20240110-amdgpu-display-enum-enum-conversion-v1-1-953ae94fe15e@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/amd/display: Avoid enum conversion warning | expand |
Applied. Thanks! On Wed, Jan 10, 2024 at 3:56 PM Nathan Chancellor <nathan@kernel.org> wrote: > > Clang warns (or errors with CONFIG_WERROR=y) when performing arithmetic > with different enumerated types, which is usually a bug: > > drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_dp_dpia_bw.c:548:24: error: arithmetic between different enumeration types ('const enum dc_link_rate' and 'const enum dc_lane_count') [-Werror,-Wenum-enum-conversion] > 548 | link_cap->link_rate * link_cap->lane_count * LINK_RATE_REF_FREQ_IN_KHZ * 8; > | ~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~ > 1 error generated. > > In this case, there is not a problem because the enumerated types are > basically treated as '#define' values. Add an explicit cast to an > integral type to silence the warning. > > Closes: https://github.com/ClangBuiltLinux/linux/issues/1976 > Fixes: 5f3bce13266e ("drm/amd/display: Request usb4 bw for mst streams") > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c > index 4ef1a6a1d129..dd0d2b206462 100644 > --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c > +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c > @@ -544,8 +544,9 @@ int link_dp_dpia_get_dp_overhead_in_dp_tunneling(struct dc_link *link) > */ > const struct dc_link_settings *link_cap = > dc_link_get_link_cap(link); > - uint32_t link_bw_in_kbps = > - link_cap->link_rate * link_cap->lane_count * LINK_RATE_REF_FREQ_IN_KHZ * 8; > + uint32_t link_bw_in_kbps = (uint32_t)link_cap->link_rate * > + (uint32_t)link_cap->lane_count * > + LINK_RATE_REF_FREQ_IN_KHZ * 8; > link_mst_overhead = (link_bw_in_kbps / 64) + ((link_bw_in_kbps % 64) ? 1 : 0); > } > > > --- > base-commit: 6e7a29f011ac03a765f53844f7c3f04cdd421715 > change-id: 20240110-amdgpu-display-enum-enum-conversion-e2451adbf4a7 > > Best regards, > -- > Nathan Chancellor <nathan@kernel.org> >
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c index 4ef1a6a1d129..dd0d2b206462 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c @@ -544,8 +544,9 @@ int link_dp_dpia_get_dp_overhead_in_dp_tunneling(struct dc_link *link) */ const struct dc_link_settings *link_cap = dc_link_get_link_cap(link); - uint32_t link_bw_in_kbps = - link_cap->link_rate * link_cap->lane_count * LINK_RATE_REF_FREQ_IN_KHZ * 8; + uint32_t link_bw_in_kbps = (uint32_t)link_cap->link_rate * + (uint32_t)link_cap->lane_count * + LINK_RATE_REF_FREQ_IN_KHZ * 8; link_mst_overhead = (link_bw_in_kbps / 64) + ((link_bw_in_kbps % 64) ? 1 : 0); }
Clang warns (or errors with CONFIG_WERROR=y) when performing arithmetic with different enumerated types, which is usually a bug: drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_dp_dpia_bw.c:548:24: error: arithmetic between different enumeration types ('const enum dc_link_rate' and 'const enum dc_lane_count') [-Werror,-Wenum-enum-conversion] 548 | link_cap->link_rate * link_cap->lane_count * LINK_RATE_REF_FREQ_IN_KHZ * 8; | ~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~ 1 error generated. In this case, there is not a problem because the enumerated types are basically treated as '#define' values. Add an explicit cast to an integral type to silence the warning. Closes: https://github.com/ClangBuiltLinux/linux/issues/1976 Fixes: 5f3bce13266e ("drm/amd/display: Request usb4 bw for mst streams") Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- base-commit: 6e7a29f011ac03a765f53844f7c3f04cdd421715 change-id: 20240110-amdgpu-display-enum-enum-conversion-e2451adbf4a7 Best regards,