Re: [PATCH v3 3/3] drm/simpledrm: Add drm_panic support

From: Thomas Zimmermann <tzimmermann@suse.de>
To: Jocelyn Falempe <jfalempe@redhat.com>,
	dri-devel@lists.freedesktop.org, airlied@redhat.com,
	maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	daniel@ffwll.ch, javierm@redhat.com,
	bluescreen_avenger@verizon.net
Cc: gpiccoli@igalia.com
Subject: Re: [PATCH v3 3/3] drm/simpledrm: Add drm_panic support
Date: Thu, 28 Sep 2023 11:33:14 +0200	[thread overview]
Message-ID: <330a87cf-45d3-4a2f-ae51-1fecb359b3c0@suse.de> (raw)
In-Reply-To: <20230927172849.193996-4-jfalempe@redhat.com>

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Hi

Am 27.09.23 um 19:22 schrieb Jocelyn Falempe:
> Add support for the drm_panic module, which displays a user-friendly
> message to the screen when a kernel panic occurs.
> 
> Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
> ---
>   drivers/gpu/drm/tiny/simpledrm.c | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
> index 25e11ef11c4c..f0454b58ead3 100644
> --- a/drivers/gpu/drm/tiny/simpledrm.c
> +++ b/drivers/gpu/drm/tiny/simpledrm.c
> @@ -23,6 +23,7 @@
>   #include <drm/drm_gem_shmem_helper.h>
>   #include <drm/drm_managed.h>
>   #include <drm/drm_modeset_helper_vtables.h>
> +#include <drm/drm_panic.h>
>   #include <drm/drm_plane_helper.h>
>   #include <drm/drm_probe_helper.h>
>   
> @@ -838,10 +839,24 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
>   		return ERR_PTR(ret);
>   
>   	drm_mode_config_reset(dev);
> +	drm_panic_register(dev);

These calls should be part of drm_device_register(). Everything should 
work transparently to the driver until DRM panic actually calls the 
get_scanout_buffer callback.

Best regards
Thomas

>   
>   	return sdev;
>   }
>   
> +static int simpledrm_get_scanout_buffer(struct drm_device *dev,
> +					struct drm_scanout_buffer *sb)
> +{
> +	struct simpledrm_device *sdev = simpledrm_device_of_dev(dev);
> +
> +	sb->width = sdev->mode.hdisplay;
> +	sb->height = sdev->mode.vdisplay;
> +	sb->pitch = sdev->pitch;
> +	sb->format = sdev->format;
> +	sb->map = sdev->screen_base;
> +	return 0;
> +}
> +
>   /*
>    * DRM driver
>    */
> @@ -857,6 +872,7 @@ static struct drm_driver simpledrm_driver = {
>   	.minor			= DRIVER_MINOR,
>   	.driver_features	= DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
>   	.fops			= &simpledrm_fops,
> +	.get_scanout_buffer	= simpledrm_get_scanout_buffer,
>   };
>   
>   /*
> @@ -894,6 +910,7 @@ static int simpledrm_remove(struct platform_device *pdev)
>   	struct drm_device *dev = &sdev->dev;
>   
>   	drm_dev_unplug(dev);
> +	drm_panic_unregister(dev);
>   
>   	return 0;
>   }

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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