Re: [PATCH v3 2/5] drm/dp: fix link probing for devices supporting DP 1.4+
From: Andrzej Hajda
Date: Thu Sep 13 2018 - 07:08:37 EST
On 28.08.2018 12:24, Damian Kos wrote:
> From: Quentin Schulz <quentin.schulz@xxxxxxxxxxx>
>
> DP 1.4 introduced a DP_EXTENDED_RCVR_CAPA_FIELD_PRESENT bit in
> DP_TRAINING_AUX_RD_INTERVAL register. If set, DPCD registers from DP_DPCD_REV
> to DP_ADAPTER_CAP should be retrieved starting from DP_DPCD_REV_EXTENDED.
> All registers are copied except DP_DPCD_REV, DP_MAX_LINK_RATE and
> DP_DOWNSTREAMPORT_PRESENT which represent the "true capabilities" of DPRX
> device.
>
> Original DP_DPCD_REV, DP_MAX_LINK_RATE and DP_DOWNSTREAMPORT_PRESENT might
> falsely return lower capabilities to "avoid interoperability issues with some
> of the existing DP Source devices that malfunction when they discover the
> higher capabilities within those three registers.".
>
> Before DP 1.4, DP_EXTENDED_RCVR_CAPA_FIELD_PRESENT bit was reserved and read 0
> so it's safe to check against it even if DP revision is <1.4
>
> Signed-off-by: Damian Kos <dkos@xxxxxxxxxxx>
Here and in next patches signed-off-by of the author is missing.
With that fixed:
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Â--
Regards
Andrzej