Coverity: dm_encoder_helper_atomic_check(): Control flow issues

[coverity-bot <keescook@chromium.org>]

Hello!

This is an experimental automated report about issues detected by Coverity
from a scan of next-20191108 as part of the linux-next weekly scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by recent commits:

5133c6241d9c ("drm/amd/display: Add MST atomic routines")

Coverity reported the following:

*** CID 1487838:  Control flow issues  (NO_EFFECT)
/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c: 4869 in dm_encoder_helper_atomic_check()
4863     		dm_new_connector_state->pbn = drm_dp_calc_pbn_mode(clock, bpp);
4864     	}
4865     	dm_new_connector_state->vcpi_slots = drm_dp_atomic_find_vcpi_slots(state,
4866     									   mst_mgr,
4867     									   mst_port,
4868     									   dm_new_connector_state->pbn);
vvv     CID 1487838:  Control flow issues  (NO_EFFECT)
vvv     This less-than-zero comparison of an unsigned value is never true. "dm_new_connector_state->vcpi_slots < 0ULL".
4869     	if (dm_new_connector_state->vcpi_slots < 0) {
4870     		DRM_DEBUG_ATOMIC("failed finding vcpi slots: %d\n", (int)dm_new_connector_state->vcpi_slots);
4871     		return dm_new_connector_state->vcpi_slots;
4872     	}
4873     	return 0;
4874     }

If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487838 ("Control flow issues")
Fixes: 5133c6241d9c ("drm/amd/display: Add MST atomic routines")


Thanks for your attention!

-- 
Coverity-bot