linux-kernel - Re: [PATCH v6] drm/msm/dp: enable HDP plugin/unplugged interrupts at hpd

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Message-ID: <3a11741c9cc699e178f9b705a34342add03ea0df@lausen.nl>
Date:   Wed, 24 May 2023 11:46:21 +0000
From:   "Leonard Lausen" <leonard@...sen.nl>
To:     "Kuogee Hsieh" <quic_khsieh@...cinc.com>,
        dri-devel@...ts.freedesktop.org, robdclark@...il.com,
        sean@...rly.run, swboyd@...omium.org, dianders@...omium.org,
        vkoul@...nel.org, daniel@...ll.ch, airlied@...il.com,
        agross@...nel.org, dmitry.baryshkov@...aro.org,
        andersson@...nel.org, regressions@...ts.linux.dev
Cc:     "Kuogee Hsieh" <quic_khsieh@...cinc.com>,
        quic_abhinavk@...cinc.com, quic_jesszhan@...cinc.com,
        quic_sbillaka@...cinc.com, marijn.suijten@...ainline.org,
        freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] drm/msm/dp: enable HDP plugin/unplugged interrupts at
 hpd_enable/disable

Kuogee Hsieh <quic_khsieh@...cinc.com> writes:
> The internal_hpd flag is set to true by dp_bridge_hpd_enable() and set to
> false by dp_bridge_hpd_disable() to handle GPIO pinmuxed into DP controller
> case. HDP related interrupts can not be enabled until internal_hpd is set
> to true. At current implementation dp_display_config_hpd() will initialize
> DP host controller first followed by enabling HDP related interrupts if
> internal_hpd was true at that time. Enable HDP related interrupts depends on
> internal_hpd status may leave system with DP driver host is in running state
> but without HDP related interrupts being enabled. This will prevent external
> display from being detected. Eliminated this dependency by moving HDP related
> interrupts enable/disable be done at dp_bridge_hpd_enable/disable() directly
> regardless of internal_hpd status.
>
> Changes in V3:
> -- dp_catalog_ctrl_hpd_enable() and dp_catalog_ctrl_hpd_disable()
> -- rewording ocmmit text
>
> Changes in V4:
> -- replace dp_display_config_hpd() with dp_display_host_start()
> -- move enable_irq() at dp_display_host_start();
>
> Changes in V5:
> -- replace dp_display_host_start() with dp_display_host_init()
>
> Changes in V6:
> -- squash remove enable_irq() and disable_irq()
>
> Fixes: cd198caddea7 ("drm/msm/dp: Rely on hpd_enable/disable callbacks")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>

Cherry-picked on top of v6.3.3 and verified fixes the USB-C DP
regression on sc7180 lazor. Thank you!

Tested-by: Leonard Lausen <leonard@...sen.nl> # on sc7180 lazor