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Message-ID: <0ac305d2-d0a9-cdfb-9be8-243402d865e7@quicinc.com>
Date: Mon, 10 Jul 2023 09:22:30 -0700
From: Kuogee Hsieh <quic_khsieh@...cinc.com>
To: Bjorn Andersson <andersson@...nel.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>, <dmitry.baryshkov@...aro.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 v1 2/5] drm/msm/dp: incorporate pm_runtime framework into
DP driver
On 7/8/2023 7:52 PM, Bjorn Andersson wrote:
> On Fri, Jul 07, 2023 at 04:52:20PM -0700, Kuogee Hsieh wrote:
>> Incorporating pm runtime framework into DP driver so that power
>> and clock resource handling can be centralized allowing easier
>> control of these resources in preparation of registering aux bus
>> uring probe.
>>
>> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
>> ---
>> drivers/gpu/drm/msm/dp/dp_aux.c | 3 ++
>> drivers/gpu/drm/msm/dp/dp_display.c | 75 +++++++++++++++++++++++++++++--------
>> 2 files changed, 63 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
>> index 8e3b677..c592064 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>> @@ -291,6 +291,7 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
>> return -EINVAL;
>> }
>>
>> + pm_runtime_get_sync(dp_aux->dev);
>> mutex_lock(&aux->mutex);
>> if (!aux->initted) {
>> ret = -EIO;
>> @@ -364,6 +365,8 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
>>
>> exit:
>> mutex_unlock(&aux->mutex);
>> + pm_runtime_mark_last_busy(dp_aux->dev);
>> + pm_runtime_put_autosuspend(dp_aux->dev);
>>
>> return ret;
>> }
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 76f1395..2c5706a 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -309,6 +309,10 @@ static int dp_display_bind(struct device *dev, struct device *master,
>> goto end;
>> }
>>
>> + pm_runtime_enable(dev);
>> + pm_runtime_set_autosuspend_delay(dev, 1000);
>> + pm_runtime_use_autosuspend(dev);
>> +
>> return 0;
>> end:
>> return rc;
>> @@ -320,9 +324,8 @@ static void dp_display_unbind(struct device *dev, struct device *master,
>> struct dp_display_private *dp = dev_get_dp_display_private(dev);
>> struct msm_drm_private *priv = dev_get_drvdata(master);
>>
>> - /* disable all HPD interrupts */
>> - if (dp->core_initialized)
>> - dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, false);
>> + pm_runtime_dont_use_autosuspend(dev);
>> + pm_runtime_disable(dev);
>>
>> kthread_stop(dp->ev_tsk);
>>
>> @@ -466,10 +469,12 @@ static void dp_display_host_init(struct dp_display_private *dp)
>> dp->dp_display.connector_type, dp->core_initialized,
>> dp->phy_initialized);
>>
>> - dp_power_init(dp->power);
>> - dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
>> - dp_aux_init(dp->aux);
>> - dp->core_initialized = true;
>> + if (!dp->core_initialized) {
>> + dp_power_init(dp->power);
>> + dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
>> + dp_aux_init(dp->aux);
>> + dp->core_initialized = true;
> There are two cases that queries core_initialized, both of those are
> done to avoid accessing the DP block without it first being powered up.
> With the introduction of runtime PM, it seems reasonable to just power
> up the block in those two code paths (and remove the variable).
>
>> + }
>> }
>>
>> static void dp_display_host_deinit(struct dp_display_private *dp)
>> @@ -478,10 +483,12 @@ static void dp_display_host_deinit(struct dp_display_private *dp)
>> dp->dp_display.connector_type, dp->core_initialized,
>> dp->phy_initialized);
>>
>> - dp_ctrl_reset_irq_ctrl(dp->ctrl, false);
>> - dp_aux_deinit(dp->aux);
>> - dp_power_deinit(dp->power);
>> - dp->core_initialized = false;
>> + if (dp->core_initialized) {
>> + dp_ctrl_reset_irq_ctrl(dp->ctrl, false);
>> + dp_aux_deinit(dp->aux);
>> + dp_power_deinit(dp->power);
>> + dp->core_initialized = false;
>> + }
>> }
>>
>> static int dp_display_usbpd_configure_cb(struct device *dev)
>> @@ -1304,6 +1311,39 @@ static int dp_display_remove(struct platform_device *pdev)
>> dp_display_deinit_sub_modules(dp);
>>
>> platform_set_drvdata(pdev, NULL);
>> + pm_runtime_put_sync_suspend(&pdev->dev);
>> +
>> + return 0;
>> +}
>> +
>> +static int dp_pm_runtime_suspend(struct device *dev)
>> +{
>> + struct platform_device *pdev = to_platform_device(dev);
>> + struct msm_dp *dp_display = platform_get_drvdata(pdev);
> platform_get_drvdata() is a wrapper for dev_get_drvdata(&pdev->dev), so
> there's no need to resolve the platform_device first...
>
>> + struct dp_display_private *dp;
>> +
>> + dp = container_of(dp_display, struct dp_display_private, dp_display);
>> +
>> + dp_display_host_phy_exit(dp);
>> + dp_catalog_ctrl_hpd_enable(dp->catalog);
>> + dp_display_host_deinit(dp);
>> +
>> + return 0;
>> +}
>> +
>> +static int dp_pm_runtime_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;
>> +
>> + dp = container_of(dp_display, struct dp_display_private, dp_display);
>> +
>> + dp_display_host_init(dp);
>> + if (dp_display->is_edp) {
>> + dp_catalog_ctrl_hpd_enable(dp->catalog);
>> + dp_display_host_phy_init(dp);
>> + }
>>
>> return 0;
>> }
>> @@ -1409,6 +1449,7 @@ 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,
>> };
>> @@ -1493,10 +1534,6 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>> aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>
>> if (aux_bus && dp->is_edp) {
>> - dp_display_host_init(dp_priv);
>> - dp_catalog_ctrl_hpd_enable(dp_priv->catalog);
>> - dp_display_host_phy_init(dp_priv);
> I'm probably just missing it, but how do we get here with the host
> powered up and the phy initialized?
if (!dp->core_initialized) is at dp_display_host_init()
>
>> -
>> /*
>> * The code below assumes that the panel will finish probing
>> * by the time devm_of_dp_aux_populate_ep_devices() returns.
>> @@ -1604,6 +1641,7 @@ void dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>> dp_hpd_plug_handle(dp_display, 0);
>>
>> mutex_lock(&dp_display->event_mutex);
>> + pm_runtime_get_sync(&dp_display->pdev->dev);
>>
>> state = dp_display->hpd_state;
>> if (state != ST_DISPLAY_OFF && state != ST_MAINLINK_READY) {
>> @@ -1684,6 +1722,8 @@ void dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
>> }
>>
>> drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
>> +
>> + pm_runtime_put_sync(&dp_display->pdev->dev);
>> mutex_unlock(&dp_display->event_mutex);
>> }
>>
>> @@ -1723,6 +1763,8 @@ 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);
>> + pm_runtime_get_sync(&dp->pdev->dev);
>> +
>> dp_catalog_ctrl_hpd_enable(dp->catalog);
>>
>> /* enable HDP interrupts */
>> @@ -1744,6 +1786,9 @@ void dp_bridge_hpd_disable(struct drm_bridge *bridge)
>> dp_catalog_ctrl_hpd_disable(dp->catalog);
>>
>> dp_display->internal_hpd = false;
>> +
>> + pm_runtime_mark_last_busy(&dp->pdev->dev);
>> + pm_runtime_put_autosuspend(&dp->pdev->dev);
>> mutex_unlock(&dp->event_mutex);
>> }
> The runtime_get/put in dp_bridge_hpd_enable() and disable matches my
> expectations. But in the case that we have an external HPD source, where
> will the power be turned on?
>
> Note that you can test this on your device by routing the HPD GPIO to a
> display-connector instance and wiring this to the DP node. In the same
> way it's done here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/qcom/sa8295p-adp.dts#n28
>
> Regards,
> Bjorn
>
>>
>> --
>> 2.7.4
>>
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