Date:	Tue, 9 Aug 2016 10:35:57 +0800
From:	Yakir Yang <ykk@...k-chips.com>
To:	Sean Paul <seanpaul@...omium.org>
Cc:	yzq@...k-chips.com, inki.dae@...sung.com, treding@...dia.com,
	heiko@...ech.de, jingoohan1@...il.com, javier@....samsung.com,
	marcheu@...omium.org, tfiga@...omium.org, dianders@...omium.org,
	airlied@...ux.ie, daniel.vetter@...ll.ch, k.kozlowski@...sung.com,
	emil.l.velikov@...il.com, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-rockchip@...ts.infradead.org,
	Archit Taneja <architt@...eaurora.org>
Subject: Re: [PATCH v2] drm/bridge: analogix_dp: Ensure the panel is properly
 prepared/unprepared

+ Archit


On 08/09/2016 02:53 AM, Sean Paul wrote:
> Instead of just preparing the panel on bind, actually prepare/unprepare
> during modeset/disable. The panel must be prepared in order to read hpd
> status and edid, so we need to keep state around the prepares in order
> to ensure we don't accidentally turn the panel off at the wrong time.
>
> Signed-off-by: Sean Paul <seanpaul@...omium.org>

Reviewed-by: Yakir Yang <ykk@...k-chips.com>

And I also tested this patch on RK3399 Kevin board, panel works rightly, so:
Tested-by: Yakir Yang <ykk@...k-chips.com>

Also add Archit into CC list, guess this patch should go through his 
drm_bridge's tree.

Thanks,
- Yakir

> ---
>
> Changes in v2:
>   - Added panel_is_modeset state/lock to avoid racing detect with modeset (marcheu)
>   - Added prepare/unprepare in .get_modes (yakir)
>
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 101 ++++++++++++++++++---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 +
>   2 files changed, 93 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 32715da..47c449a 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -923,11 +923,63 @@ static void analogix_dp_commit(struct analogix_dp_device *dp)
>   	analogix_dp_start_video(dp);
>   }
>   
> +/*
> + * This function is a bit of a catch-all for panel preparation, hopefully
> + * simplifying the logic of functions that need to prepare/unprepare the panel
> + * below.
> + *
> + * If @prepare is true, this function will prepare the panel. Conversely, if it
> + * is false, the panel will be unprepared.
> + *
> + * If @is_modeset_prepare is true, the function will disregard the current state
> + * of the panel and either prepare/unprepare the panel based on @prepare. Once
> + * it finishes, it will update dp->panel_is_modeset to reflect the current state
> + * of the panel.
> + */
> +static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
> +				     bool prepare, bool is_modeset_prepare)
> +{
> +	int ret = 0;
> +
> +	if (!dp->plat_data->panel)
> +		return 0;
> +
> +	mutex_lock(&dp->panel_lock);
> +
> +	/*
> +	 * Exit early if this is a temporary prepare/unprepare and we're already
> +	 * modeset (since we neither want to prepare twice or unprepare early).
> +	 */
> +	if (dp->panel_is_modeset && !is_modeset_prepare)
> +		goto out;
> +
> +	if (prepare)
> +		ret = drm_panel_prepare(dp->plat_data->panel);
> +	else
> +		ret = drm_panel_unprepare(dp->plat_data->panel);
> +
> +	if (ret)
> +		goto out;
> +
> +	if (is_modeset_prepare)
> +		dp->panel_is_modeset = prepare;
> +
> +out:
> +	mutex_unlock(&dp->panel_lock);
> +	return ret;
> +}
> +
>   int analogix_dp_get_modes(struct drm_connector *connector)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
>   	struct edid *edid = (struct edid *)dp->edid;
> -	int num_modes = 0;
> +	int ret, num_modes = 0;
> +
> +	ret = analogix_dp_prepare_panel(dp, true, false);
> +	if (ret) {
> +		DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> +		return 0;
> +	}
>   
>   	if (analogix_dp_handle_edid(dp) == 0) {
>   		drm_mode_connector_update_edid_property(&dp->connector, edid);
> @@ -940,6 +992,10 @@ int analogix_dp_get_modes(struct drm_connector *connector)
>   	if (dp->plat_data->get_modes)
>   		num_modes += dp->plat_data->get_modes(dp->plat_data, connector);
>   
> +	ret = analogix_dp_prepare_panel(dp, false, false);
> +	if (ret)
> +		DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> +
>   	return num_modes;
>   }
>   
> @@ -960,11 +1016,23 @@ enum drm_connector_status
>   analogix_dp_detect(struct drm_connector *connector, bool force)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
> +	enum drm_connector_status status = connector_status_disconnected;
> +	int ret;
>   
> -	if (analogix_dp_detect_hpd(dp))
> +	ret = analogix_dp_prepare_panel(dp, true, false);
> +	if (ret) {
> +		DRM_ERROR("Failed to prepare panel (%d)\n", ret);
>   		return connector_status_disconnected;
> +	}
> +
> +	if (!analogix_dp_detect_hpd(dp))
> +		status = connector_status_connected;
>   
> -	return connector_status_connected;
> +	ret = analogix_dp_prepare_panel(dp, false, false);
> +	if (ret)
> +		DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> +
> +	return status;
>   }
>   
>   static void analogix_dp_connector_destroy(struct drm_connector *connector)
> @@ -1035,6 +1103,16 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge)
>   	return 0;
>   }
>   
> +static void analogix_dp_bridge_pre_enable(struct drm_bridge *bridge)
> +{
> +	struct analogix_dp_device *dp = bridge->driver_private;
> +	int ret;
> +
> +	ret = analogix_dp_prepare_panel(dp, true, true);
> +	if (ret)
> +		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +}
> +
>   static void analogix_dp_bridge_enable(struct drm_bridge *bridge)
>   {
>   	struct analogix_dp_device *dp = bridge->driver_private;
> @@ -1058,6 +1136,7 @@ static void analogix_dp_bridge_enable(struct drm_bridge *bridge)
>   static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   {
>   	struct analogix_dp_device *dp = bridge->driver_private;
> +	int ret;
>   
>   	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
>   		return;
> @@ -1077,6 +1156,10 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> +	ret = analogix_dp_prepare_panel(dp, false, true);
> +	if (ret)
> +		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   }
>   
> @@ -1165,9 +1248,9 @@ static void analogix_dp_bridge_nop(struct drm_bridge *bridge)
>   }
>   
>   static const struct drm_bridge_funcs analogix_dp_bridge_funcs = {
> +	.pre_enable = analogix_dp_bridge_pre_enable,
>   	.enable = analogix_dp_bridge_enable,
>   	.disable = analogix_dp_bridge_disable,
> -	.pre_enable = analogix_dp_bridge_nop,
>   	.post_disable = analogix_dp_bridge_nop,
>   	.mode_set = analogix_dp_bridge_mode_set,
>   	.attach = analogix_dp_bridge_attach,
> @@ -1254,6 +1337,9 @@ int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev,
>   	dp->dev = &pdev->dev;
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
> +	mutex_init(&dp->panel_lock);
> +	dp->panel_is_modeset = false;
> +
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
>   	 * the driver private data, so we need to store the point of
> @@ -1333,13 +1419,6 @@ int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev,
>   
>   	phy_power_on(dp->phy);
>   
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_prepare(dp->plat_data->panel)) {
> -			DRM_ERROR("failed to setup the panel\n");
> -			return -EBUSY;
> -		}
> -	}
> -
>   	analogix_dp_init_dp(dp);
>   
>   	ret = devm_request_threaded_irq(&pdev->dev, dp->irq,
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index b456380..43108d7 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -178,6 +178,9 @@ struct analogix_dp_device {
>   	bool                    force_hpd;
>   	unsigned char           edid[EDID_BLOCK_LENGTH * 2];
>   
> +	struct mutex		panel_lock;
> +	bool			panel_is_modeset;
> +
>   	struct analogix_dp_plat_data *plat_data;
>   };
>   

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