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Date: Tue, 3 Oct 2023 09:43:56 -0700
From: Kuogee Hsieh <quic_khsieh@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
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 v4 7/8] drm/msm/dp: add
pm_runtime_force_suspend()/resume()
On 9/27/2023 3:00 PM, Dmitry Baryshkov wrote:
> On Wed, 27 Sept 2023 at 23:54, Kuogee Hsieh <quic_khsieh@...cinc.com> wrote:
>> After incorporated pm_runtime framework into eDP/DP driver, the
> incorporating
>
>
>> original 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 since
>> those function are replaced by dp_pm_runtime_suspend() and
>> dp_pm_runtime_resume() through pm runtime framework.
>> Therefore add pm framework provides functions,
>> pm_runtime_force_suspend()/resume() to complete incorporating pm
>> runtime framework into DP driver.
>>
>> Changes in v4:
>> -- 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:
>> -- 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 | 113 ++----------------------------------
>> 1 file changed, 5 insertions(+), 108 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 9158a2c..711d262 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -49,7 +49,6 @@ enum {
>> ST_CONNECTED,
>> ST_DISCONNECT_PENDING,
>> ST_DISPLAY_OFF,
>> - ST_SUSPENDED,
>> };
>>
>> enum {
>> @@ -560,7 +559,7 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
>> drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
>> dp->dp_display.connector_type, state);
>>
>> - if (state == ST_DISPLAY_OFF || state == ST_SUSPENDED) {
>> + if (state == ST_DISPLAY_OFF) {
>> mutex_unlock(&dp->event_mutex);
>> return 0;
>> }
>> @@ -674,7 +673,7 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
>> drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
>> dp->dp_display.connector_type, state);
>>
>> - if (state == ST_DISPLAY_OFF || state == ST_SUSPENDED) {
>> + if (state == ST_DISPLAY_OFF) {
>> mutex_unlock(&dp->event_mutex);
>> return 0;
>> }
>> @@ -1321,110 +1320,10 @@ static int dp_pm_runtime_resume(struct device *dev)
>> return 0;
>> }
>>
>> -static int dp_pm_resume(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);
>> -
>> - 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);
>> -
>> - /* 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)
>> -{
>> - 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);
>> -
>> - 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);
> I was under the impression that dp_pm_runtime_suspend / _resume
> functions perform phy init/exit only in eDP cases. Can we really drop
> the main suspend/resume functions?
yes on eDP case since it is embedded.
for external DP case, there are two steps
step 1: enable DP controller's hpd block and start waiting for hpd
interrupts at dp_display_hpd_enable()
step 2: at plugin interrupts, dp_display_host_phy_init()
step 3: at unplug interrupt: dp_bridge_atomic_post_disable()
dp_display_host_phy_exi()
at runtime, there is loop between step 2 and step 3
step 4: disable DP controller's hpd block
>
>> -
>> - /* 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;
>> -}
>> -
>> 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)
>> };
>>
>> static struct platform_driver dp_display_driver = {
>> @@ -1658,9 +1557,6 @@ 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);
> Why?
dp_hpd_unplug_handle() does not tear down phy.
Therefore eDP does not need to call unplug handle.
>> -
>> mutex_lock(&dp_display->event_mutex);
>>
>> state = dp_display->hpd_state;
>> @@ -1748,6 +1644,7 @@ void dp_bridge_hpd_disable(struct drm_bridge *bridge)
>> dp_catalog_ctrl_hpd_disable(dp->catalog);
>>
>> dp_display->internal_hpd = false;
>> + dp->hpd_state = ST_DISCONNECTED;
> Why? We have only disabled sending of the HPD events. The dongle might
> still be connected.
dp_bridge_hpd_disable() disable dp controller hpd block (no more hpd
interrupt will be received).
dp_bridge_hpd_disable() should happen after DP main link had been teared
down already.
Therefore hpd_state need to be in default state so that next plugin
handle will be start with correct state.
>
>> pm_runtime_mark_last_busy(&dp->pdev->dev);
>> pm_runtime_put_autosuspend(&dp->pdev->dev);
>> --
>> 2.7.4
>>
>
> --
> With best wishes
>
> Dmitry
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