On 10.03.2017 05:32, Sean Paul wrote:
> From: zain wang <w...@rock-chips.com>
>
> According to DP spec v1.3 chap 3.5.1.2 Link Training, Link Policy Maker
> must first detect that the HPD signal is asserted high by the Downstream
> Device before establishing a link with it.
>
> Cc: Stéphane Marchesin <marc...@chromium.org>
> Signed-off-by: zain wang <w...@rock-chips.com>
> Signed-off-by: Sean Paul <seanp...@chromium.org>
> ---
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index f3eea7636a2e..048b6f7c9b6e 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1172,6 +1172,15 @@ static int analogix_dp_set_bridge(struct
> analogix_dp_device *dp)
> if (ret)
> goto out_dp_init;
>
> + /* According to DP spec v1.3 chap 3.5.1.2 Link Training,
> + * We should first make sure the HPD signal is asserted high by device
> + * when we want to establish a link with it. */
> + ret = analogix_dp_detect_hpd(dp);
> + if (ret) {
> + DRM_ERROR("failed to get hpd single ret = %d\n", ret);
> + goto out_dp_init;
> + }
> +
With previous patch analogix_dp_set_bridge will be repeated even if hpd
is low, is it desired behavior?
Regards
Andrzej
> ret = analogix_dp_commit(dp);
> if (ret)
> goto out_dp_init;
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