Re: [PATCH 0/3] drm/amd/display: HDMI FRL training fixes for slow sinks

[Andrzej Piątyszek]

Please drop this series.

As Sashiko pointed out, patch 2 raises the LTS:3 timeout past the HDMI
T_FLT limit, which commits f38686268b0d and 007834be6760 tuned for
compliance. I'll send a v2 that keeps patch 1 as a general fix and
enables the rest only for the affected TV, through an EDID quirk.

Thanks,
Andrzej


wt., 10 lis 2026 o 14:15 Andrzej Piątyszek
<andrzej.piatyszek@xxxxxxxxx> napisał(a):
>
> With FRL on by default since commit 5fd3b60d9b80 ("drm/amd/display:
> Enable HDMI FRL by default"), an RX 9070 XT mostly trains a Samsung
> QE65Q80T (2020) at 6 Gbps x 3, where 4K 120 Hz needs DSC. Windows on
> the same machine trains it at 10 Gbps x 4.
>
> The TV needs one TxFFE step at 10 Gbps x 4, but requested levels never
> reach the PHY; with patch 1, the driver programs them right away. The
> TV sometimes answers an LTP request only after up to 967 ms, while the
> driver waits only 220 ms in LTS:3; patch 2 raises the limit to 1 s.
> After waking up, the TV can stay silent at 10 Gbps x 4 for up to about
> four seconds, but link verification gives up on that rate after one
> attempt; with patch 3, verification tries the same rate again first, as
> the enable path does.
>
> Tested on 7.3 with an equivalent backport. Without the series, 4 of 6
> boots and TV wake-ups ended at 6 Gbps x 3. With patches 1 and 2, 16 of
> 20 reached 10 Gbps x 4, and the other 4 are the case patch 3 handles.
> With all three, all 63 boots and TV wake-ups over 12 days reached
> 10 Gbps x 4. In 13 of them the sink stayed silent at first during link
> verification and answered after one to three more attempts at the same
> rate. On amd-staging-drm-next the series is build-tested only.
>
> Andrzej Piątyszek (3):
>   drm/amd/display: Apply requested TxFFE level right away in FRL
>     training
>   drm/amd/display: Wait up to 1 s for slow sinks in FRL link training
>   drm/amd/display: Retry the same FRL rate after a sink timeout
>
>  .../display/dc/link/protocols/link_hdmi_frl.c | 56 +++++++++++--------
>  1 file changed, 33 insertions(+), 23 deletions(-)
>
>
> base-commit: 47df73aa49d1988c8f684b7caf8be6570e966844
> --
> 2.56.0
>