[PATCH] drm/vboxvideo: Vmap/vunmap cursor BO in prepare_fb and cleanup_fb

Thomas Zimmermann tzimmermann at suse.de
Wed Feb 3 10:34:21 UTC 2021


Hi

Am 03.02.21 um 11:29 schrieb Daniel Vetter:
> On Wed, Jan 27, 2021 at 03:05:03PM +0100, Thomas Zimmermann wrote:
>> Functions in the atomic commit tail are not allowed to acquire the
>> dmabuf's reservation lock. So we cannot legally call the GEM object's
>> vmap functionality in atomic_update.
>>
>> Instead vmap the cursor BO in prepare_fb and vunmap it in cleanup_fb.
>> The cursor plane state stores the mapping's address. The pinning of the
>> BO is implicitly done by vmap.
>>
>> As an extra benefit, there's no source of runtime errors left in
>> atomic_update.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> 
> Did you test this with my dma_fence_signalling annotations patches?

Not with vbox. I did test similar code in my recent ast patchset. But I 
think there's still a bug here, as there's no custom plane-reset function.

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

I'll certainly send out an updated patch.

Best regards
Thomas

> 
>> ---
>>   drivers/gpu/drm/vboxvideo/vbox_mode.c | 102 +++++++++++++++++++++-----
>>   1 file changed, 82 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vboxvideo/vbox_mode.c b/drivers/gpu/drm/vboxvideo/vbox_mode.c
>> index dbc0dd53c69e..b5625a7d6cef 100644
>> --- a/drivers/gpu/drm/vboxvideo/vbox_mode.c
>> +++ b/drivers/gpu/drm/vboxvideo/vbox_mode.c
>> @@ -324,6 +324,19 @@ static void vbox_primary_atomic_disable(struct drm_plane *plane,
>>   				    old_state->src_y >> 16);
>>   }
>>   
>> +struct vbox_cursor_plane_state {
>> +	struct drm_plane_state base;
>> +
>> +	/* Transitional state - do not export or duplicate */
>> +
>> +	struct dma_buf_map map;
>> +};
>> +
>> +static struct vbox_cursor_plane_state *to_vbox_cursor_plane_state(struct drm_plane_state *state)
>> +{
>> +	return container_of(state, struct vbox_cursor_plane_state, base);
>> +}
>> +
>>   static int vbox_cursor_atomic_check(struct drm_plane *plane,
>>   				    struct drm_plane_state *new_state)
>>   {
>> @@ -381,14 +394,13 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>>   		container_of(plane->dev, struct vbox_private, ddev);
>>   	struct vbox_crtc *vbox_crtc = to_vbox_crtc(plane->state->crtc);
>>   	struct drm_framebuffer *fb = plane->state->fb;
>> -	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(fb->obj[0]);
>>   	u32 width = plane->state->crtc_w;
>>   	u32 height = plane->state->crtc_h;
>> +	struct vbox_cursor_plane_state *vbox_state = to_vbox_cursor_plane_state(plane->state);
>> +	struct dma_buf_map map = vbox_state->map;
>> +	u8 *src = map.vaddr; /* TODO: Use mapping abstraction properly */
>>   	size_t data_size, mask_size;
>>   	u32 flags;
>> -	struct dma_buf_map map;
>> -	int ret;
>> -	u8 *src;
>>   
>>   	/*
>>   	 * VirtualBox uses the host windowing system to draw the cursor so
>> @@ -401,17 +413,6 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>>   
>>   	vbox_crtc->cursor_enabled = true;
>>   
>> -	ret = drm_gem_vram_vmap(gbo, &map);
>> -	if (ret) {
>> -		/*
>> -		 * BUG: we should have pinned the BO in prepare_fb().
>> -		 */
>> -		mutex_unlock(&vbox->hw_mutex);
>> -		DRM_WARN("Could not map cursor bo, skipping update\n");
>> -		return;
>> -	}
>> -	src = map.vaddr; /* TODO: Use mapping abstraction properly */
>> -
>>   	/*
>>   	 * The mask must be calculated based on the alpha
>>   	 * channel, one bit per ARGB word, and must be 32-bit
>> @@ -421,7 +422,6 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>>   	data_size = width * height * 4 + mask_size;
>>   
>>   	copy_cursor_image(src, vbox->cursor_data, width, height, mask_size);
>> -	drm_gem_vram_vunmap(gbo, &map);
>>   
>>   	flags = VBOX_MOUSE_POINTER_VISIBLE | VBOX_MOUSE_POINTER_SHAPE |
>>   		VBOX_MOUSE_POINTER_ALPHA;
>> @@ -458,6 +458,43 @@ static void vbox_cursor_atomic_disable(struct drm_plane *plane,
>>   	mutex_unlock(&vbox->hw_mutex);
>>   }
>>   
>> +static int vbox_cursor_prepare_fb(struct drm_plane *plane, struct drm_plane_state *new_state)
>> +{
>> +	struct vbox_cursor_plane_state *new_vbox_state = to_vbox_cursor_plane_state(new_state);
>> +	struct drm_framebuffer *fb = new_state->fb;
>> +	struct drm_gem_vram_object *gbo;
>> +	struct dma_buf_map map;
>> +	int ret;
>> +
>> +	if (!fb)
>> +		return 0;
>> +
>> +	gbo = drm_gem_vram_of_gem(fb->obj[0]);
>> +
>> +	ret = drm_gem_vram_vmap(gbo, &map);
>> +	if (ret)
>> +		return ret;
>> +
>> +	new_vbox_state->map = map;
>> +
>> +	return 0;
>> +}
>> +
>> +static void vbox_cursor_cleanup_fb(struct drm_plane *plane, struct drm_plane_state *old_state)
>> +{
>> +	struct vbox_cursor_plane_state *old_vbox_state = to_vbox_cursor_plane_state(old_state);
>> +	struct drm_framebuffer *fb = old_state->fb;
>> +	struct dma_buf_map map = old_vbox_state->map;
>> +	struct drm_gem_vram_object *gbo;
>> +
>> +	if (!fb)
>> +		return;
>> +
>> +	gbo = drm_gem_vram_of_gem(fb->obj[0]);
>> +
>> +	drm_gem_vram_vunmap(gbo, &map);
>> +}
>> +
>>   static const u32 vbox_cursor_plane_formats[] = {
>>   	DRM_FORMAT_ARGB8888,
>>   };
>> @@ -466,17 +503,42 @@ static const struct drm_plane_helper_funcs vbox_cursor_helper_funcs = {
>>   	.atomic_check	= vbox_cursor_atomic_check,
>>   	.atomic_update	= vbox_cursor_atomic_update,
>>   	.atomic_disable	= vbox_cursor_atomic_disable,
>> -	.prepare_fb	= drm_gem_vram_plane_helper_prepare_fb,
>> -	.cleanup_fb	= drm_gem_vram_plane_helper_cleanup_fb,
>> +	.prepare_fb	= vbox_cursor_prepare_fb,
>> +	.cleanup_fb	= vbox_cursor_cleanup_fb,
>>   };
>>   
>> +static struct drm_plane_state *vbox_cursor_atomic_duplicate_state(struct drm_plane *plane)
>> +{
>> +	struct vbox_cursor_plane_state *new_vbox_state;
>> +	struct drm_device *dev = plane->dev;
>> +
>> +	if (drm_WARN_ON(dev, !plane->state))
>> +		return NULL;
>> +
>> +	new_vbox_state = kzalloc(sizeof(*new_vbox_state), GFP_KERNEL);
>> +	if (!new_vbox_state)
>> +		return NULL;
>> +	__drm_atomic_helper_plane_duplicate_state(plane, &new_vbox_state->base);
>> +
>> +	return &new_vbox_state->base;
>> +}
>> +
>> +static void vbox_cursor_atomic_destroy_state(struct drm_plane *plane,
>> +					     struct drm_plane_state *state)
>> +{
>> +	struct vbox_cursor_plane_state *vbox_state = to_vbox_cursor_plane_state(state);
>> +
>> +	__drm_atomic_helper_plane_destroy_state(&vbox_state->base);
>> +	kfree(vbox_state);
>> +}
>> +
>>   static const struct drm_plane_funcs vbox_cursor_plane_funcs = {
>>   	.update_plane	= drm_atomic_helper_update_plane,
>>   	.disable_plane	= drm_atomic_helper_disable_plane,
>>   	.destroy	= drm_primary_helper_destroy,
>>   	.reset		= drm_atomic_helper_plane_reset,
>> -	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
>> -	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
>> +	.atomic_duplicate_state = vbox_cursor_atomic_duplicate_state,
>> +	.atomic_destroy_state = vbox_cursor_atomic_destroy_state,
>>   };
>>   
>>   static const u32 vbox_primary_plane_formats[] = {
>>
>> base-commit: 3836b7fdfad40e2bac5dc882332f42bed6942cf4
>> prerequisite-patch-id: c2b2f08f0eccc9f5df0c0da49fa1d36267deb11d
>> -- 
>> 2.30.0
>>
> 

-- 
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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