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Subject: Re: [PATCH 1/2] drm/msm/dp: postpone irq_hpd event during connection pending state
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     Kuogee Hsieh <khsieh@codeaurora.org>, tanmay@codeaurora.org,
        abhinavk@codeaurora.org, aravindh@codeaurora.org, airlied@linux.ie,
        daniel@ffwll.ch, linux-arm-msm@vger.kernel.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
To:     Kuogee Hsieh <khsieh@codeaurora.org>,
        dri-devel@lists.freedesktop.org, robdclark@gmail.com,
        sean@poorly.run
Date:   Mon, 11 Jan 2021 11:55:18 -0800
Message-ID: <161039491877.3661239.1387205899512360969@swboyd.mtv.corp.google.com>
User-Agent: alot/0.9.1
Precedence: bulk

Quoting Kuogee Hsieh (2021-01-07 12:30:24)
> irq_hpd event can only be executed at connected state. Therefore
> irq_hpd event should be postponed if it happened at connection
> pending state. This patch also make sure both link rate and lane

Why does it happen at connection pending state?

> are valid before start link training.

Can this part about link rate and lane being valid be split off into
another patch?

>=20
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Any fixes tag?

>  drivers/gpu/drm/msm/dp/dp_display.c |  7 +++++++
>  drivers/gpu/drm/msm/dp/dp_panel.c   | 12 +++++++++---
>  2 files changed, 16 insertions(+), 3 deletions(-)
>=20
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp=
/dp_display.c
> index 6e971d5..3bc7ed2 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -693,6 +693,13 @@ static int dp_irq_hpd_handle(struct dp_display_priva=
te *dp, u32 data)
>                 return 0;
>         }
> =20
> +       if (state =3D=3D ST_CONNECT_PENDING) {
> +               /* wait until ST_CONNECTED */
> +               dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay =3D 1 */
> +               mutex_unlock(&dp->event_mutex);
> +               return 0;
> +       }
> +
>         ret =3D dp_display_usbpd_attention_cb(&dp->pdev->dev);
>         if (ret =3D=3D -ECONNRESET) { /* cable unplugged */
>                 dp->core_initialized =3D false;