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Date:   Tue, 11 Feb 2020 15:22:42 +0100
From:   Daniel Vetter <daniel@ffwll.ch>
To:     Gerd Hoffmann <kraxel@redhat.com>
Cc:     dri-devel@lists.freedesktop.org, Dave Airlie <airlied@redhat.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" 
        <virtualization@lists.linux-foundation.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4] drm/cirrus: add drm_driver.release callback.
Message-ID: <20200211142242.GD2363188@phenom.ffwll.local>
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        dri-devel@lists.freedesktop.org, Dave Airlie <airlied@redhat.com>,
        David Airlie <airlied@linux.ie>,
        "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" <virtualization@lists.linux-foundation.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20200211135522.23654-1-kraxel@redhat.com>
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On Tue, Feb 11, 2020 at 02:55:22PM +0100, Gerd Hoffmann wrote:
> Move final cleanups from cirrus_pci_remove() to the new callback.
> Add drm_atomic_helper_shutdown() call to cirrus_pci_remove().
> 
> Use drm_dev_{enter,exit,unplug} to avoid touching hardware after
> device removal.
> 
> v4: add changelog.
> v3: use drm_dev*.
> v2: stop touching hardware after pci_remove().
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

I think you got them all with drm_dev_enter/exit.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Aside: everyone ignores the return value of cirrus_fb_blit_rect and
cirrus_mode_set (with atomic those shouldn't be able to fail anymore),
could ditch those.
-Daniel

> ---
>  drivers/gpu/drm/cirrus/cirrus.c | 43 ++++++++++++++++++++++++++++-----
>  1 file changed, 37 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/cirrus/cirrus.c b/drivers/gpu/drm/cirrus/cirrus.c
> index a91fb0d7282c..d2ff63ce8eaf 100644
> --- a/drivers/gpu/drm/cirrus/cirrus.c
> +++ b/drivers/gpu/drm/cirrus/cirrus.c
> @@ -151,9 +151,13 @@ static int cirrus_pitch(struct drm_framebuffer *fb)
>  
>  static void cirrus_set_start_address(struct cirrus_device *cirrus, u32 offset)
>  {
> +	int idx;
>  	u32 addr;
>  	u8 tmp;
>  
> +	if (!drm_dev_enter(&cirrus->dev, &idx))
> +		return;
> +
>  	addr = offset >> 2;
>  	wreg_crt(cirrus, 0x0c, (u8)((addr >> 8) & 0xff));
>  	wreg_crt(cirrus, 0x0d, (u8)(addr & 0xff));
> @@ -168,6 +172,8 @@ static void cirrus_set_start_address(struct cirrus_device *cirrus, u32 offset)
>  	tmp &= 0x7f;
>  	tmp |= (addr >> 12) & 0x80;
>  	wreg_crt(cirrus, 0x1d, tmp);
> +
> +	drm_dev_exit(idx);
>  }
>  
>  static int cirrus_mode_set(struct cirrus_device *cirrus,
> @@ -176,9 +182,12 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
>  {
>  	int hsyncstart, hsyncend, htotal, hdispend;
>  	int vtotal, vdispend;
> -	int tmp;
> +	int tmp, idx;
>  	int sr07 = 0, hdr = 0;
>  
> +	if (!drm_dev_enter(&cirrus->dev, &idx))
> +		return -1;
> +
>  	htotal = mode->htotal / 8;
>  	hsyncend = mode->hsync_end / 8;
>  	hsyncstart = mode->hsync_start / 8;
> @@ -264,6 +273,7 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
>  		hdr = 0xc5;
>  		break;
>  	default:
> +		drm_dev_exit(idx);
>  		return -1;
>  	}
>  
> @@ -292,6 +302,8 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
>  
>  	/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
>  	outb(0x20, 0x3c0);
> +
> +	drm_dev_exit(idx);
>  	return 0;
>  }
>  
> @@ -300,10 +312,16 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
>  {
>  	struct cirrus_device *cirrus = fb->dev->dev_private;
>  	void *vmap;
> +	int idx, ret;
>  
> +	ret = -ENODEV;
> +	if (!drm_dev_enter(&cirrus->dev, &idx))
> +		goto out;
> +
> +	ret = -ENOMEM;
>  	vmap = drm_gem_shmem_vmap(fb->obj[0]);
>  	if (!vmap)
> -		return -ENOMEM;
> +		goto out_dev_exit;
>  
>  	if (cirrus->cpp == fb->format->cpp[0])
>  		drm_fb_memcpy_dstclip(cirrus->vram,
> @@ -323,7 +341,12 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
>  		WARN_ON_ONCE("cpp mismatch");
>  
>  	drm_gem_shmem_vunmap(fb->obj[0], vmap);
> -	return 0;
> +	ret = 0;
> +
> +out_dev_exit:
> +	drm_dev_exit(idx);
> +out:
> +	return ret;
>  }
>  
>  static int cirrus_fb_blit_fullscreen(struct drm_framebuffer *fb)
> @@ -502,6 +525,14 @@ static void cirrus_mode_config_init(struct cirrus_device *cirrus)
>  
>  /* ------------------------------------------------------------------ */
>  
> +static void cirrus_release(struct drm_device *dev)
> +{
> +	struct cirrus_device *cirrus = dev->dev_private;
> +
> +	drm_mode_config_cleanup(dev);
> +	kfree(cirrus);
> +}
> +
>  DEFINE_DRM_GEM_FOPS(cirrus_fops);
>  
>  static struct drm_driver cirrus_driver = {
> @@ -515,6 +546,7 @@ static struct drm_driver cirrus_driver = {
>  
>  	.fops		 = &cirrus_fops,
>  	DRM_GEM_SHMEM_DRIVER_OPS,
> +	.release         = cirrus_release,
>  };
>  
>  static int cirrus_pci_probe(struct pci_dev *pdev,
> @@ -598,12 +630,11 @@ static void cirrus_pci_remove(struct pci_dev *pdev)
>  	struct drm_device *dev = pci_get_drvdata(pdev);
>  	struct cirrus_device *cirrus = dev->dev_private;
>  
> -	drm_dev_unregister(dev);
> -	drm_mode_config_cleanup(dev);
> +	drm_dev_unplug(dev);
> +	drm_atomic_helper_shutdown(dev);
>  	iounmap(cirrus->mmio);
>  	iounmap(cirrus->vram);
>  	drm_dev_put(dev);
> -	kfree(cirrus);
>  	pci_release_regions(pdev);
>  }
>  
> -- 
> 2.18.2
> 

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