[PATCH 6.6 206/299] drm/amd/display: Avoid enum conversion warning

Greg Kroah-Hartman
2024-02-27T13:56:16Z

From: Nathan Chancellor <nathan@kernel.org>

commit d7643fe6fb76edb1f2f1497bf5e8b8f4774b5129 upstream.

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>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- 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_t
*/
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);
}