linux-kernel - Re: [PATCH v2 2/2] drm/komeda: Adds komeda_kms_drop_master

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Date:   Tue, 11 Jun 2019 14:30:38 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     "Lowry Li (Arm Technology China)" <Lowry.Li@....com>
Cc:     Liviu Dudau <Liviu.Dudau@....com>,
        "james qian wang (Arm Technology China)" <james.qian.wang@....com>,
        "maarten.lankhorst@...ux.intel.com" 
        <maarten.lankhorst@...ux.intel.com>,
        "seanpaul@...omium.org" <seanpaul@...omium.org>,
        "airlied@...ux.ie" <airlied@...ux.ie>,
        Brian Starkey <Brian.Starkey@....com>,
        Ayan Halder <Ayan.Halder@....com>,
        "Jonathan Chai (Arm Technology China)" <Jonathan.Chai@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "Julien Yin (Arm Technology China)" <Julien.Yin@....com>,
        nd <nd@....com>
Subject: Re: [PATCH v2 2/2] drm/komeda: Adds komeda_kms_drop_master

On Tue, Jun 11, 2019 at 11:13:45AM +0000, Lowry Li (Arm Technology China) wrote:
> From: "Lowry Li (Arm Technology China)" <Lowry.Li@....com>
> 
> The komeda internal resources (pipelines) are shared between crtcs,
> and resources release by disable_crtc. This commit is working for once
> user forgot disabling crtc like app quit abnomally, and then the
> resources can not be used by another crtc. Adds drop_master to
> shutdown the device and make sure all the komeda resources have been
> released and can be used for the next usage.
> 
> Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@....com>
> ---
>  drivers/gpu/drm/arm/display/komeda/komeda_kms.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> index 8543860..647bce5 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> @@ -54,11 +54,24 @@ static irqreturn_t komeda_kms_irq_handler(int irq, void *data)
>  	return status;
>  }
>  
> +/* Komeda internal resources (pipelines) are shared between crtcs, and resources
> + * are released by disable_crtc. But if user forget disabling crtc like app quit
> + * abnormally, the resources can not be used by another crtc.
> + * Use drop_master to shutdown the device and make sure all the komeda resources
> + * have been released, and can be used for the next usage.
> + */

No. If we want this, we need to implement this across drivers, not with
per-vendor hacks.

The kerneldoc should have been a solid hint: "Only used by vmwgfx."
-Daniel

> +static void komeda_kms_drop_master(struct drm_device *dev,
> +				   struct drm_file *file_priv)
> +{
> +	drm_atomic_helper_shutdown(dev);
> +}
> +
>  static struct drm_driver komeda_kms_driver = {
>  	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC |
>  			   DRIVER_PRIME | DRIVER_HAVE_IRQ,
>  	.lastclose			= drm_fb_helper_lastclose,
>  	.irq_handler			= komeda_kms_irq_handler,
> +	.master_drop			= komeda_kms_drop_master,
>  	.gem_free_object_unlocked	= drm_gem_cma_free_object,
>  	.gem_vm_ops			= &drm_gem_cma_vm_ops,
>  	.dumb_create			= komeda_gem_cma_dumb_create,
> -- 
> 1.9.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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

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