drm/amd/display: Add HDMI 2.1 VRR support for HF-VSDB

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why:
HDMI 2.1 sinks advertise their VRR range in the HDMI Forum VSDB
(HF-VSDB), but amdgpu derived FreeSync capability only from the AMD
VSDB. Sinks that expose just the HDMI Forum VRR capability (e.g. HDMI
compliance EDIDs) were therefore reported as not VRR capable.

how:
- In amdgpu_dm_update_freesync_caps(), when the AMD VSDB does not
  provide a valid FreeSync range, fall back to the HDMI 2.1 VRR range
  parsed by DRM core from the HF-VSDB
  (connector->display_info.hdmi.vrr_cap). VRRMAX = 0 means "up to the
  Base Refresh Rate"; when the EDID provides no monitor range maximum
  either, fall back to the Base Refresh Rate (the highest refresh-rate
  mode of the preferred timing) so a valid VRR range is still reported
  to userspace.
- Add VRR debug logging along the FreeSync capability and config paths.

Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Fangzhi Zuo 2026-07-24 16:00:02 -04:00 • committed by Alex Deucher

parent 6675c4642b

commit fa3389c713

2 changed files with 75 additions and 0 deletions

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67

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c

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8

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c

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