Re: [PATCH] drm/amd/display: Avoid enum conversion warning
Applied. Thanks!
On Wed, Jan 10, 2024 at 3:56 PM Nathan Chancellor 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
> ---
> 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
>
[PATCH] drm/amd/display: Avoid enum conversion warning
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
---
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
