linux-kernel - Re: [PATCH v5 5/7] drm/msm/dp: incorporate pm

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Message-ID: <CAA8EJprAQqNUvY8CMkKbUNEWo1vO1ZkgZzk4zhvAsuLc46KeXg@mail.gmail.com>
Date:   Fri, 6 Oct 2023 20:56:31 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Kuogee Hsieh <quic_khsieh@...cinc.com>
Cc:     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, andersson@...nel.org, 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 v5 5/7] drm/msm/dp: incorporate pm_runtime framework into
 DP driver

On Wed, 4 Oct 2023 at 19:27, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
>
> Currently DP driver is executed independent of PM runtime framework.
> This leads msm eDP panel can not being detected by edp_panel driver during
> generic_edp_panel_probe() due to AUX DPCD read failed at edp panel driver.
> Incorporate PM runtime framework into DP driver so that host controller's
> power and clocks are enable/disable through PM runtime mechanism.
> Once PM runtime framework is incorporated into DP driver, waking up device
> from power up path is not necessary. Hence remove it.
>
> After incorporating pm_runtime framework into eDP/DP driver, dp_pm_suspend()
> to handle power off both DP phy and controller during suspend and
> dp_pm_resume() to handle power on both DP phy and controller during resume
> are not necessary. Therefore both dp_pm_suspend() and dp_pm_resume() are
> dropped and replace with dp_pm_runtime_suspend() and dp_pm_runtime_resume()
> respectively.
>
> Changes in v5:
> -- remove pm_runtime_put_autosuspend feature, use pm_runtime_put_sync() directly
> -- squash add pm_runtime_force_suspend()/resume() patch into this patch
>
> Changes in v4:
> -- reworded commit text to explain why pm_framework is required for edp panel
> -- reworded commit text to explain autosuspend is choiced
> -- delete EV_POWER_PM_GET and PM_EV_POWER_PUT from changes #3
> -- delete dp_display_pm_get() and dp_display_pm_Put() from changes #3
> -- return value from pm_runtime_resume_and_get() directly
> -- check return value of devm_pm_runtime_enable()
> -- delete pm_runtime_xxx from dp_display_remove()
> -- drop dp_display_host_init() from EV_HPD_INIT_SETUP
> -- drop both dp_pm_prepare() and dp_pm_compete() from this change
> -- delete ST_SUSPENDED state
> -- rewording commit text to add more details regrading the purpose
>    of this change
>
> Changes in v3:
> -- incorporate removing pm_runtime_xx() from dp_pwer.c to this patch
> -- use pm_runtime_resume_and_get() instead of pm_runtime_get()
> -- error checking pm_runtime_resume_and_get() return value
> -- add EV_POWER_PM_GET and PM_EV_POWER_PUT to handle HPD_GPIO case
> -- replace dp_pm_suspend() with pm_runtime_force_suspend()
> -- replace dp_pm_resume() with pm_runtime_force_resume()
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
> Reported-by: kernel test robot <lkp@...el.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_aux.c     |   5 ++
>  drivers/gpu/drm/msm/dp/dp_display.c | 166 ++++++++++++------------------------
>  drivers/gpu/drm/msm/dp/dp_power.c   |  16 ----
>  drivers/gpu/drm/msm/dp/dp_power.h   |  11 ---
>  4 files changed, 59 insertions(+), 139 deletions(-)

[skipped]

> @@ -1702,6 +1638,12 @@ void dp_bridge_hpd_enable(struct drm_bridge *bridge)
>         struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
>
>         mutex_lock(&dp->event_mutex);
> +       if (pm_runtime_resume_and_get(&dp->pdev->dev)) {
> +               DRM_ERROR("failed to start power\n");

It was in the previous review comment:

"failed to resume".

> +               mutex_unlock(&dp->event_mutex);
> +               return;
> +       }
> +

-- 
With best wishes
Dmitry