Re: [PATCH v2] drm/rockchip: remove existing generic drivers to take over the device

From: Thomas Zimmermann <tzimmermann@suse.de>
To: Javier Martinez Canillas <javierm@redhat.com>,
	linux-kernel@vger.kernel.org
Cc: "Peter Robinson" <pbrobinson@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"David Airlie" <airlied@linux.ie>,
	"Heiko Stübner" <heiko@sntech.de>,
	"Sandy Huang" <hjc@rock-chips.com>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v2] drm/rockchip: remove existing generic drivers to take over the device
Date: Sun, 16 May 2021 12:30:32 +0200	[thread overview]
Message-ID: <ef974dd8-5619-35b7-74de-4e270033a3c3@suse.de> (raw)
In-Reply-To: <20210516074833.451643-1-javierm@redhat.com>

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Am 16.05.21 um 09:48 schrieb Javier Martinez Canillas:
> There are drivers that register framebuffer devices very early in the boot
> process and make use of the existing framebuffer as setup by the firmware.
> 
> If one of those drivers has registered a fbdev, then the fallback fbdev 
of
> the DRM driver won't be bound to the framebuffer console. To avoid that,
> remove any existing generic driver and take over the graphics device.
> 
> By doing that, the fb mapped to the console is switched correctly from the
> early fbdev to the one registered by the rockchip DRM driver:
> 
>      [   40.752420] fb0: switching to rockchip-drm-fb from EFI VGA
> 
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

Ping me if no one else merges the patch.

Best regards
Thomas

> ---
> 
> Changes in v2:
> - Move drm_aperture_remove_framebuffers() call to .bind callback (tzimmermann).
> - Adapt subject line, commit message, etc accordingly.
> 
>   drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> index 212bd87c0c4..b730b8d5d94 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> @@ -16,6 +16,7 @@
>   #include <linux/console.h>
>   #include <linux/iommu.h>
>   
> +#include <drm/drm_aperture.h>
>   #include <drm/drm_drv.h>
>   #include <drm/drm_fb_helper.h>
>   #include <drm/drm_gem_cma_helper.h>
> @@ -114,6 +115,15 @@ static int rockchip_drm_bind(struct device *dev)
>   	struct rockchip_drm_private *private;
>   	int ret;
>   
> +	/* Remove existing drivers that may own the framebuffer memory. */
> +	ret = drm_aperture_remove_framebuffers(false, "rockchip-drm-fb");
> +	if (ret) {
> +		DRM_DEV_ERROR(dev,
> +			      "Failed to remove existing framebuffers - %d.\n",
> +			      ret);
> +		return ret;
> +	}
> +
>   	drm_dev = drm_dev_alloc(&rockchip_drm_driver, dev);
>   	if (IS_ERR(drm_dev))
>   		return PTR_ERR(drm_dev);
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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