Re: [PATCH 2/2] drm/i915/display: allow eDP VRR when EDID has adaptive sync range

[Jake S <j@metarealtyinc.ca>]

Hi Ville,

> It's in the LFP power block (44).

You're right -- I checked and intel_vbt_decode shows:

  BDB block 44 - LFP power conservation features block:
    Variable Refresh Rate (VRR): yes

And looking at the code, panel->vbt.vrr defaults to true at line
1370 of intel_bios.c anyway. So the VBT gate was never the problem.

The actual issue is the final check in intel_vrr_is_capable():

  return info->monitor_range.max_vfreq - min_vfreq > 10;

monitor_range is 0/0 because this panel's EDID has no base block
Range Limits descriptor (tag 0xFD). The VRR range is only in the
DisplayID v2.0 Adaptive Sync block (tag 0x2B), which drm_edid.c
doesn't parse into monitor_range.

So patch 2/2 (the VBT relaxation) is unnecessary and I'll drop it.
Only patch 1/2 (parsing DisplayID tag 0x2B into monitor_range) is
needed. I'll send a v2 with just that patch.

Sorry for the noise on the VBT front -- should have traced the
actual failure path more carefully before assuming.

Thanks,
Jake