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Subject: Re: [PATCH v4] drm/msm/dp: return correct connection status after suspend
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     tanmay@codeaurora.org, abhinavk@codeaurora.org,
        aravindh@codeaurora.org, khsieh@codeaurora.org, airlied@linux.ie,
        daniel@ffwll.ch, linux-arm-msm@vger.kernel.org,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
To:     Kuogee Hsieh <khsieh@codeaurora.org>, robdclark@gmail.com,
        sean@poorly.run
Date:   Tue, 13 Oct 2020 17:36:52 -0700
Message-ID: <160263581242.310579.522359444728182805@swboyd.mtv.corp.google.com>
User-Agent: alot/0.9.1
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Quoting Kuogee Hsieh (2020-10-13 16:35:22)
> During suspend, dp host controller and hpd block are disabled due to
> both ahb and aux clock are disabled. Therefore hpd plug/unplug interrupts
> will not be generated. At dp_pm_resume(), reinitialize both dp host
> controller and hpd block so that hpd plug/unplug interrupts will be
> generated and handled by driver so that hpd connection state is updated
> correctly. This patch will fix link training flaky issues.
>=20
> Changes in v2:
> -- use container_of to cast correct dp_display_private pointer
>    at both dp_pm_suspend() and dp_pm_resume().
>=20
> Changes in v3:
> -- replace hpd_state atomic_t  with u32
>=20
> Changes in v4
> -- call dp_display_host_deinit() at dp_pm_suspend()
> -- call dp_display_host_init() at msm_dp_display_enable()
> -- fix phy->init_count unbalance which causes link training failed
>=20
> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> ---

Can we add some sort of Fixes tag? Maybe the beginning of this DP driver
support?

Tested-by: Stephen Boyd <swboyd@chromium.org>