Re: [PATCH v2 12/12] JUST FOR TEST: Add one-shot trigger to update display

From: Daniel Vetter <daniel-/w4YWyX8dFk@public.gmane.org>
To: Mark Zhang <markz-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	daniel-/w4YWyX8dFk@public.gmane.org,
	linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: Re: [PATCH v2 12/12] JUST FOR TEST: Add one-shot trigger to update display
Date: Wed, 1 Jul 2015 10:36:17 +0200	[thread overview]
Message-ID: <20150701083617.GF30960@phenom.ffwll.local> (raw)
In-Reply-To: <1435738915-31973-13-git-send-email-markz-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

On Wed, Jul 01, 2015 at 04:21:55PM +0800, Mark Zhang wrote:
> This HACK adds a workqueue to refresh the display periodically.
> This is used just for testing.

->dirty is the drm hook you're looking for, it's meant to flush out any
frontbuffer rendering. Generic kms clients using the dumb buffers (e.g.
fedora boot splash) use this already.

And of course you need to upload a new frame every time an (atomic) flip
happens too, but I guess you have that already. No need at all for a
periodic upload hack like this.

Cheers, Daniel

> 
> Signed-off-by: Mark Zhang <markz-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/gpu/drm/tegra/dc.c  |   37 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/tegra/drm.h |    1 +
>  2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
> index 24a91613c4f5..4381691c73f7 100644
> --- a/drivers/gpu/drm/tegra/dc.c
> +++ b/drivers/gpu/drm/tegra/dc.c
> @@ -1296,6 +1296,8 @@ static void tegra_crtc_mode_set_nofb(struct drm_crtc *crtc)
>  		value &= ~DISP_CTRL_MODE_MASK;
>  		value |= DISP_CTRL_MODE_NC_DISPLAY;
>  		tegra_dc_writel(dc, value, DC_CMD_DISPLAY_COMMAND);
> +
> +		schedule_work(&dc->one_shot_trigger);
>  	} else {
>  		value = tegra_dc_readl(dc, DC_CMD_DISPLAY_COMMAND);
>  		value &= ~DISP_CTRL_MODE_MASK;
> @@ -1958,6 +1960,40 @@ static void tegra_dc_one_shot_work(struct work_struct *work)
>  	drm_modeset_unlock_all(drm);
>  }
>  
> +static void tegra_dc_one_shot_trigger(struct work_struct *work)
> +{
> +	struct tegra_dc *dc;
> +	struct drm_connector *connector;
> +	struct drm_device *drm;
> +	unsigned long update_mask = GENERAL_ACT_REQ | NC_HOST_TRIG;
> +	static int first_trigger = 1;
> +
> +	dc = container_of(work, struct tegra_dc, one_shot_trigger);
> +	drm = dc->base.dev;
> +	msleep(5000);
> +
> +	if (first_trigger) {
> +		dev_info(dc->dev, "First one-shot triggered.\n");
> +		tegra_dc_writel(dc, update_mask, DC_CMD_STATE_CONTROL);
> +		first_trigger = 0;
> +		schedule_work(&dc->one_shot_trigger);
> +		return;
> +	}
> +
> +	dev_info(dc->dev, "one-shot: Wakeup dc/dsi/panel.\n");
> +	drm_modeset_lock_all(drm);
> +	list_for_each_entry(connector, &drm->mode_config.connector_list, head) {
> +		if (connector->funcs->dpms)
> +			connector->funcs->dpms(connector,
> +						DRM_MODE_DPMS_STANDBY);
> +	}
> +	drm_modeset_unlock_all(drm);
> +
> +	/* Trigger the one-shot */
> +	tegra_dc_writel(dc, update_mask, DC_CMD_STATE_CONTROL);
> +	schedule_work(&dc->one_shot_trigger);
> +}
> +
>  static int tegra_dc_probe(struct platform_device *pdev)
>  {
>  	unsigned long flags = HOST1X_SYNCPT_CLIENT_MANAGED;
> @@ -1977,6 +2013,7 @@ static int tegra_dc_probe(struct platform_device *pdev)
>  	spin_lock_init(&dc->lock);
>  	INIT_LIST_HEAD(&dc->list);
>  	INIT_WORK(&dc->one_shot_work, tegra_dc_one_shot_work);
> +	INIT_WORK(&dc->one_shot_trigger, tegra_dc_one_shot_trigger);
>  	dc->dev = &pdev->dev;
>  	dc->soc = id->data;
>  
> diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> index 00daf427c831..5d606cacb098 100644
> --- a/drivers/gpu/drm/tegra/drm.h
> +++ b/drivers/gpu/drm/tegra/drm.h
> @@ -132,6 +132,7 @@ struct tegra_dc {
>  	struct drm_pending_vblank_event *event;
>  
>  	struct work_struct one_shot_work;
> +	struct work_struct one_shot_trigger;
>  
>  	const struct tegra_dc_soc_info *soc;
>  
> -- 
> 1.7.9.5
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch