[PATCHv2 11/22] drm/bridge: tc358767: ensure DP is disabled before LT

[Andrzej Hajda]

On 26.03.2019 11:31, Tomi Valkeinen wrote:
> Link training will sometimes fail if the DP link is, for some whatever
> reason, enabled when tc_main_link_enable() is called.


Only tc_stream_enable enables it, does it mean that link training can
happen after tc_stream_enable?

It suggests that driver/device preforms strange things, is it true? Or
just overprotection?


Regards

Andrzej


>
> Ensure that the DP link is disabled by setting DP0CTL to 0 as the first
> thing.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> ---
>  drivers/gpu/drm/bridge/tc358767.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index fe5fd7db0247..f628575c9de9 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -839,6 +839,8 @@ static int tc_main_link_enable(struct tc_data *tc)
>  
>  	dev_dbg(tc->dev, "link enable\n");
>  
> +	tc_write(DP0CTL, 0);
> +



>  	tc_write(DP0_SRCCTRL, tc_srcctrl(tc));
>  	/* SSCG and BW27 on DP1 must be set to the same as on DP0 */
>  	tc_write(DP1_SRCCTRL,