drm/amd/display: restore FRL cap on non-destructive HDMI link verify

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[Why&How]
Restore the FRL verified cap from the reported cap so a link whose FRL
pre-training was skipped (e.g. skip_frl_pre_training) stays on FRL across
a hotplug instead of falling back to TMDS.

On hotplug the HDMI sink is recreated as SIGNAL_TYPE_HDMI_TYPE_A and
only the destructive verify path promotes it to FRL via
hdmi_frl_verify_link_cap(). When the non-destructive path runs - which is
what the skip_frl_pre_training quirk forces on an already-active link -
the HDMI branch mistakenly assigned the DP verified_link_cap from
reported_link_cap and left frl_verified_link_cap stale. With
frl_link_rate reading back as HDMI_FRL_LINK_RATE_DISABLE, the stream
collapsed to TMDS. Assign frl_verified_link_cap from
frl_reported_link_cap (populated during detection by
hdmi_frl_retrieve_link_cap()) to match the reference DM behavior and keep
the link on FRL.

Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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Fangzhi Zuo 2026-07-30 16:47:46 -04:00 • committed by Alex Deucher

parent 435f359a23

commit 482b6542a8

1 changed files with 1 additions and 1 deletions

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drivers/gpu/drm/amd/display/dc/link/link_detection.c

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