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Message-ID: <CAA8EJpr2wRq6Txi7YAQpJKa_9UGqH_nmHzvVOaAPkwOrtDg4Tw@mail.gmail.com>
Date: Tue, 19 Sep 2023 12:50:12 +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 v3 6/7] drm/msm/dp: add pm_runtime_force_suspend()/resume()
On Mon, 18 Sept 2023 at 20:48, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
>
>
> On 9/15/2023 6:21 PM, Dmitry Baryshkov wrote:
> > On Sat, 16 Sept 2023 at 00:38, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
> >> Add pm_runtime_force_suspend()/resume() to complete incorporating pm
> >> runtime framework into DP driver. Both dp_pm_prepare() and dp_pm_complete()
> >> are added to set hpd_state to correct state. After resume, DP driver will
> >> re training its main link after .hpd_enable() callback enabled HPD
> >> interrupts and bring up display accordingly.
> > How will it re-train the main link? What is the code path for that?
>
> 1) for edp, dp_bridge_atomic_enable(), called from framework, to start
> link training and bring up display.
And this path doesn't use .hpd_enable() which you have mentioned in
the commit message. Please don't try to shorten the commit message.
You see, I have had questions to several of them, which means that
they were not verbose enough.
>
> 2) for external DP, HPD_PLUG_INT will be generated to start link
> training and bring up display.
This should be hpd_notify, who starts link training, not some event.
>
> >
> > I think this is a misuse for prepare/complete callbacks, at least
> > judging from their documentation.
>
> 1) dp_pm_prepare() is called to make sure eDP/DP related power/clocks
> are off and set hpd_state to ST_SUSPENDED and nothing else.
>
> 2) dp_pm_completed() is called to set hpd_state to ST_ST_DISCONNECTED
> (default state) and nothing else.
>
> I think both are doing proper action.
Have you read the prepare() / complete() documentation? Does your
usage follow the documented use case?
>
>
> >
> >> Changes in v3:
> >> -- 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>
> >> ---
> >> drivers/gpu/drm/msm/dp/dp_display.c | 87 +++++--------------------------------
> >> 1 file changed, 10 insertions(+), 77 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> >> index b6992202..b58cb02 100644
> >> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> >> @@ -1333,101 +1333,35 @@ static int dp_pm_runtime_resume(struct device *dev)
> >> return 0;
> >> }
> >>
> >> -static int dp_pm_resume(struct device *dev)
> >> +static void dp_pm_complete(struct device *dev)
> >> {
> >> - struct platform_device *pdev = to_platform_device(dev);
> >> - struct msm_dp *dp_display = platform_get_drvdata(pdev);
> >> - struct dp_display_private *dp;
> >> - int sink_count = 0;
> >> -
> >> - dp = container_of(dp_display, struct dp_display_private, dp_display);
> >> + struct dp_display_private *dp = dev_get_dp_display_private(dev);
> >>
> >> mutex_lock(&dp->event_mutex);
> >>
> >> drm_dbg_dp(dp->drm_dev,
> >> - "Before, type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> >> + "type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> >> dp->dp_display.connector_type, dp->core_initialized,
> >> - dp->phy_initialized, dp_display->power_on);
> >> + dp->phy_initialized, dp->dp_display.power_on);
> >>
> >> /* start from disconnected state */
> >> dp->hpd_state = ST_DISCONNECTED;
> >>
> >> - /* turn on dp ctrl/phy */
> >> - dp_display_host_init(dp);
> >> -
> >> - if (dp_display->is_edp)
> >> - dp_catalog_ctrl_hpd_enable(dp->catalog);
> >> -
> >> - if (dp_catalog_link_is_connected(dp->catalog)) {
> >> - /*
> >> - * set sink to normal operation mode -- D0
> >> - * before dpcd read
> >> - */
> >> - dp_display_host_phy_init(dp);
> >> - dp_link_psm_config(dp->link, &dp->panel->link_info, false);
> >> - sink_count = drm_dp_read_sink_count(dp->aux);
> >> - if (sink_count < 0)
> >> - sink_count = 0;
> >> -
> >> - dp_display_host_phy_exit(dp);
> >> - }
> >> -
> >> - dp->link->sink_count = sink_count;
> >> - /*
> >> - * can not declared display is connected unless
> >> - * HDMI cable is plugged in and sink_count of
> >> - * dongle become 1
> >> - * also only signal audio when disconnected
> >> - */
> >> - if (dp->link->sink_count) {
> >> - dp->dp_display.link_ready = true;
> >> - } else {
> >> - dp->dp_display.link_ready = false;
> >> - dp_display_handle_plugged_change(dp_display, false);
> >> - }
> >> -
> >> - drm_dbg_dp(dp->drm_dev,
> >> - "After, type=%d sink=%d conn=%d core_init=%d phy_init=%d power=%d\n",
> >> - dp->dp_display.connector_type, dp->link->sink_count,
> >> - dp->dp_display.link_ready, dp->core_initialized,
> >> - dp->phy_initialized, dp_display->power_on);
> >> -
> >> mutex_unlock(&dp->event_mutex);
> >> -
> >> - return 0;
> >> }
> >>
> >> -static int dp_pm_suspend(struct device *dev)
> >> +static int dp_pm_prepare(struct device *dev)
> >> {
> >> - struct platform_device *pdev = to_platform_device(dev);
> >> - struct msm_dp *dp_display = platform_get_drvdata(pdev);
> >> - struct dp_display_private *dp;
> >> -
> >> - dp = container_of(dp_display, struct dp_display_private, dp_display);
> >> + struct dp_display_private *dp = dev_get_dp_display_private(dev);
> >>
> >> mutex_lock(&dp->event_mutex);
> >>
> >> - drm_dbg_dp(dp->drm_dev,
> >> - "Before, type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> >> - dp->dp_display.connector_type, dp->core_initialized,
> >> - dp->phy_initialized, dp_display->power_on);
> >> -
> >> /* mainlink enabled */
> >> if (dp_power_clk_status(dp->power, DP_CTRL_PM))
> >> dp_ctrl_off_link_stream(dp->ctrl);
> >>
> >> - dp_display_host_phy_exit(dp);
> >> -
> >> - /* host_init will be called at pm_resume */
> >> - dp_display_host_deinit(dp);
> >> -
> >> dp->hpd_state = ST_SUSPENDED;
> >>
> >> - drm_dbg_dp(dp->drm_dev,
> >> - "After, type=%d core_inited=%d phy_inited=%d power_on=%d\n",
> >> - dp->dp_display.connector_type, dp->core_initialized,
> >> - dp->phy_initialized, dp_display->power_on);
> >> -
> >> mutex_unlock(&dp->event_mutex);
> >>
> >> return 0;
> >> @@ -1435,8 +1369,10 @@ static int dp_pm_suspend(struct device *dev)
> >>
> >> static const struct dev_pm_ops dp_pm_ops = {
> >> SET_RUNTIME_PM_OPS(dp_pm_runtime_suspend, dp_pm_runtime_resume, NULL)
> >> - .suspend = dp_pm_suspend,
> >> - .resume = dp_pm_resume,
> >> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> >> + pm_runtime_force_resume)
> >> + .prepare = dp_pm_prepare,
> >> + .complete = dp_pm_complete,
> >> };
> >>
> >> static struct platform_driver dp_display_driver = {
> >> @@ -1670,9 +1606,6 @@ void dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
> >>
> >> dp_display = container_of(dp, struct dp_display_private, dp_display);
> >>
> >> - if (dp->is_edp)
> >> - dp_hpd_unplug_handle(dp_display, 0);
> >> -
> >> mutex_lock(&dp_display->event_mutex);
> >>
> >> state = dp_display->hpd_state;
> >> --
> >> 2.7.4
> >>
> >
--
With best wishes
Dmitry
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