Claude review: drm/i915/dp: Compute and include coasting vtotal for AS SDP

Claude Code Review Bot
2026-04-12T02:51:30Z

Patch Review

**R-b: Ville Syrjala**

Adds coasting vtotal to the AS SDP pack, unpack, and comparison. Sets it during late compute for PR with Aux-less ALPM when async video timing is supported:
```c
if (intel_alpm_is_alpm_aux_less(intel_dp, crtc_state) &&
intel_psr_pr_async_video_timing_supported(intel_dp))
as_sdp->coasting_vtotal = crtc_state->vrr.vmax;
```

Using `vrr.vmax` as the coasting vtotal (minimum refresh rate) is the safe default.

No issues.