[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / gpu / drm / vmwgfx / vmwgfx_ioctl.c

/**************************************************************************
 *
 * Copyright © 2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

#include "vmwgfx_drv.h"
#include "vmwgfx_drm.h"
#include "vmwgfx_kms.h"

int vmw_getparam_ioctl(struct drm_device *dev, void *data,
		       struct drm_file *file_priv)
{
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct drm_vmw_getparam_arg *param =
	    (struct drm_vmw_getparam_arg *)data;

	switch (param->param) {
	case DRM_VMW_PARAM_NUM_STREAMS:
		param->value = vmw_overlay_num_overlays(dev_priv);
		break;
	case DRM_VMW_PARAM_NUM_FREE_STREAMS:
		param->value = vmw_overlay_num_free_overlays(dev_priv);
		break;
	case DRM_VMW_PARAM_3D:
		param->value = vmw_fifo_have_3d(dev_priv) ? 1 : 0;
		break;
	case DRM_VMW_PARAM_HW_CAPS:
		param->value = dev_priv->capabilities;
		break;
	case DRM_VMW_PARAM_FIFO_CAPS:
		param->value = dev_priv->fifo.capabilities;
		break;
	case DRM_VMW_PARAM_MAX_FB_SIZE:
		param->value = dev_priv->vram_size;
		break;
	case DRM_VMW_PARAM_FIFO_HW_VERSION:
	{
		__le32 __iomem *fifo_mem = dev_priv->mmio_virt;

		param->value = ioread32(fifo_mem + SVGA_FIFO_3D_HWVERSION);
		break;
	}
	default:
		DRM_ERROR("Illegal vmwgfx get param request: %d\n",
			  param->param);
		return -EINVAL;
	}

	return 0;
}


int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
			 struct drm_file *file_priv)
{
	struct drm_vmw_get_3d_cap_arg *arg =
		(struct drm_vmw_get_3d_cap_arg *) data;
	struct vmw_private *dev_priv = vmw_priv(dev);
	uint32_t size;
	__le32 __iomem *fifo_mem;
	void __user *buffer = (void __user *)((unsigned long)(arg->buffer));
	void *bounce;
	int ret;

	if (unlikely(arg->pad64 != 0)) {
		DRM_ERROR("Illegal GET_3D_CAP argument.\n");
		return -EINVAL;
	}

	size = (SVGA_FIFO_3D_CAPS_LAST - SVGA_FIFO_3D_CAPS + 1) << 2;

	if (arg->max_size < size)
		size = arg->max_size;

	bounce = vmalloc(size);
	if (unlikely(bounce == NULL)) {
		DRM_ERROR("Failed to allocate bounce buffer for 3D caps.\n");
		return -ENOMEM;
	}

	fifo_mem = dev_priv->mmio_virt;
	memcpy_fromio(bounce, &fifo_mem[SVGA_FIFO_3D_CAPS], size);

	ret = copy_to_user(buffer, bounce, size);
	vfree(bounce);

	if (unlikely(ret != 0))
		DRM_ERROR("Failed to report 3D caps info.\n");

	return ret;
}

int vmw_present_ioctl(struct drm_device *dev, void *data,
		      struct drm_file *file_priv)
{
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct drm_vmw_present_arg *arg =
		(struct drm_vmw_present_arg *)data;
	struct vmw_surface *surface;
	struct vmw_master *vmaster = vmw_master(file_priv->master);
	struct drm_vmw_rect __user *clips_ptr;
	struct drm_vmw_rect *clips = NULL;
	struct drm_mode_object *obj;
	struct vmw_framebuffer *vfb;
	uint32_t num_clips;
	int ret;

	num_clips = arg->num_clips;
	clips_ptr = (struct drm_vmw_rect *)(unsigned long)arg->clips_ptr;

	if (unlikely(num_clips == 0))
		return 0;

	if (clips_ptr == NULL) {
		DRM_ERROR("Variable clips_ptr must be specified.\n");
		ret = -EINVAL;
		goto out_clips;
	}

	clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
	if (clips == NULL) {
		DRM_ERROR("Failed to allocate clip rect list.\n");
		ret = -ENOMEM;
		goto out_clips;
	}

	ret = copy_from_user(clips, clips_ptr, num_clips * sizeof(*clips));
	if (ret) {
		DRM_ERROR("Failed to copy clip rects from userspace.\n");
		ret = -EFAULT;
		goto out_no_copy;
	}

	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
	if (unlikely(ret != 0)) {
		ret = -ERESTARTSYS;
		goto out_no_mode_mutex;
	}

	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
	if (!obj) {
		DRM_ERROR("Invalid framebuffer id.\n");
		ret = -EINVAL;
		goto out_no_fb;
	}

	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
	if (!vfb->dmabuf) {
		DRM_ERROR("Framebuffer not dmabuf backed.\n");
		ret = -EINVAL;
		goto out_no_fb;
	}

	ret = ttm_read_lock(&vmaster->lock, true);
	if (unlikely(ret != 0))
		goto out_no_ttm_lock;

	ret = vmw_user_surface_lookup_handle(dev_priv, tfile, arg->sid,
					     &surface);
	if (ret)
		goto out_no_surface;

	ret = vmw_kms_present(dev_priv, file_priv,
			      vfb, surface, arg->sid,
			      arg->dest_x, arg->dest_y,
			      clips, num_clips);

	/* vmw_user_surface_lookup takes one ref so does new_fb */
	vmw_surface_unreference(&surface);

out_no_surface:
	ttm_read_unlock(&vmaster->lock);
out_no_ttm_lock:
out_no_fb:
	mutex_unlock(&dev->mode_config.mutex);
out_no_mode_mutex:
out_no_copy:
	kfree(clips);
out_clips:
	return ret;
}

int vmw_present_readback_ioctl(struct drm_device *dev, void *data,
			       struct drm_file *file_priv)
{
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct drm_vmw_present_readback_arg *arg =
		(struct drm_vmw_present_readback_arg *)data;
	struct drm_vmw_fence_rep __user *user_fence_rep =
		(struct drm_vmw_fence_rep __user *)
		(unsigned long)arg->fence_rep;
	struct vmw_master *vmaster = vmw_master(file_priv->master);
	struct drm_vmw_rect __user *clips_ptr;
	struct drm_vmw_rect *clips = NULL;
	struct drm_mode_object *obj;
	struct vmw_framebuffer *vfb;
	uint32_t num_clips;
	int ret;

	num_clips = arg->num_clips;
	clips_ptr = (struct drm_vmw_rect *)(unsigned long)arg->clips_ptr;

	if (unlikely(num_clips == 0))
		return 0;

	if (clips_ptr == NULL) {
		DRM_ERROR("Argument clips_ptr must be specified.\n");
		ret = -EINVAL;
		goto out_clips;
	}

	clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
	if (clips == NULL) {
		DRM_ERROR("Failed to allocate clip rect list.\n");
		ret = -ENOMEM;
		goto out_clips;
	}

	ret = copy_from_user(clips, clips_ptr, num_clips * sizeof(*clips));
	if (ret) {
		DRM_ERROR("Failed to copy clip rects from userspace.\n");
		ret = -EFAULT;
		goto out_no_copy;
	}

	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
	if (unlikely(ret != 0)) {
		ret = -ERESTARTSYS;
		goto out_no_mode_mutex;
	}

	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
	if (!obj) {
		DRM_ERROR("Invalid framebuffer id.\n");
		ret = -EINVAL;
		goto out_no_fb;
	}

	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
	if (!vfb->dmabuf) {
		DRM_ERROR("Framebuffer not dmabuf backed.\n");
		ret = -EINVAL;
		goto out_no_fb;
	}

	ret = ttm_read_lock(&vmaster->lock, true);
	if (unlikely(ret != 0))
		goto out_no_ttm_lock;

	ret = vmw_kms_readback(dev_priv, file_priv,
			       vfb, user_fence_rep,
			       clips, num_clips);

	ttm_read_unlock(&vmaster->lock);
out_no_ttm_lock:
out_no_fb:
	mutex_unlock(&dev->mode_config.mutex);
out_no_mode_mutex:
out_no_copy:
	kfree(clips);
out_clips:
	return ret;
}


/**
 * vmw_fops_poll - wrapper around the drm_poll function
 *
 * @filp: See the linux fops poll documentation.
 * @wait: See the linux fops poll documentation.
 *
 * Wrapper around the drm_poll function that makes sure the device is
 * processing the fifo if drm_poll decides to wait.
 */
unsigned int vmw_fops_poll(struct file *filp, struct poll_table_struct *wait)
{
	struct drm_file *file_priv = filp->private_data;
	struct vmw_private *dev_priv =
		vmw_priv(file_priv->minor->dev);

	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
	return drm_poll(filp, wait);
}


/**
 * vmw_fops_read - wrapper around the drm_read function
 *
 * @filp: See the linux fops read documentation.
 * @buffer: See the linux fops read documentation.
 * @count: See the linux fops read documentation.
 * offset: See the linux fops read documentation.
 *
 * Wrapper around the drm_read function that makes sure the device is
 * processing the fifo if drm_read decides to wait.
 */
ssize_t vmw_fops_read(struct file *filp, char __user *buffer,
		      size_t count, loff_t *offset)
{
	struct drm_file *file_priv = filp->private_data;
	struct vmw_private *dev_priv =
		vmw_priv(file_priv->minor->dev);

	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
	return drm_read(filp, buffer, count, offset);
}
Commit	Line	Data
fb1d9738 JB	1	/**************************************************************************
	2	*
	3	* Copyright © 2009 VMware, Inc., Palo Alto, CA., USA
	4	* All Rights Reserved.
	5	*
	6	* Permission is hereby granted, free of charge, to any person obtaining a
	7	* copy of this software and associated documentation files (the
	8	* "Software"), to deal in the Software without restriction, including
	9	* without limitation the rights to use, copy, modify, merge, publish,
	10	* distribute, sub license, and/or sell copies of the Software, and to
	11	* permit persons to whom the Software is furnished to do so, subject to
	12	* the following conditions:
	13	*
	14	* The above copyright notice and this permission notice (including the
	15	* next paragraph) shall be included in all copies or substantial portions
	16	* of the Software.
	17	*
	18	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	19	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	20	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	21	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	22	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	23	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	24	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	25	*
	26	**************************************************************************/
	27
	28	#include "vmwgfx_drv.h"
	29	#include "vmwgfx_drm.h"
2fcd5a73	30	#include "vmwgfx_kms.h"
fb1d9738 JB	31
	32	int vmw_getparam_ioctl(struct drm_device dev, void data,
	33	struct drm_file *file_priv)
	34	{
	35	struct vmw_private *dev_priv = vmw_priv(dev);
	36	struct drm_vmw_getparam_arg *param =
	37	(struct drm_vmw_getparam_arg *)data;
	38
	39	switch (param->param) {
	40	case DRM_VMW_PARAM_NUM_STREAMS:
	41	param->value = vmw_overlay_num_overlays(dev_priv);
	42	break;
	43	case DRM_VMW_PARAM_NUM_FREE_STREAMS:
	44	param->value = vmw_overlay_num_free_overlays(dev_priv);
	45	break;
	46	case DRM_VMW_PARAM_3D:
8e19a951	47	param->value = vmw_fifo_have_3d(dev_priv) ? 1 : 0;
fb1d9738	48	break;
f77cef3d TH	49	case DRM_VMW_PARAM_HW_CAPS:
	50	param->value = dev_priv->capabilities;
	51	break;
	52	case DRM_VMW_PARAM_FIFO_CAPS:
	53	param->value = dev_priv->fifo.capabilities;
	54	break;
30f47fc8 TH	55	case DRM_VMW_PARAM_MAX_FB_SIZE:
	56	param->value = dev_priv->vram_size;
	57	break;
f63f6a59 TH	58	case DRM_VMW_PARAM_FIFO_HW_VERSION:
	59	{
	60	__le32 __iomem *fifo_mem = dev_priv->mmio_virt;
	61
	62	param->value = ioread32(fifo_mem + SVGA_FIFO_3D_HWVERSION);
	63	break;
	64	}
fb1d9738 JB	65	default:
	66	DRM_ERROR("Illegal vmwgfx get param request: %d\n",
	67	param->param);
	68	return -EINVAL;
	69	}
	70
	71	return 0;
	72	}
f63f6a59 TH	73
	74
	75	int vmw_get_cap_3d_ioctl(struct drm_device dev, void data,
	76	struct drm_file *file_priv)
	77	{
	78	struct drm_vmw_get_3d_cap_arg *arg =
	79	(struct drm_vmw_get_3d_cap_arg *) data;
	80	struct vmw_private *dev_priv = vmw_priv(dev);
	81	uint32_t size;
	82	__le32 __iomem *fifo_mem;
	83	void __user buffer = (void __user )((unsigned long)(arg->buffer));
	84	void *bounce;
	85	int ret;
	86
	87	if (unlikely(arg->pad64 != 0)) {
	88	DRM_ERROR("Illegal GET_3D_CAP argument.\n");
	89	return -EINVAL;
	90	}
	91
	92	size = (SVGA_FIFO_3D_CAPS_LAST - SVGA_FIFO_3D_CAPS + 1) << 2;
	93
	94	if (arg->max_size < size)
	95	size = arg->max_size;
	96
	97	bounce = vmalloc(size);
	98	if (unlikely(bounce == NULL)) {
	99	DRM_ERROR("Failed to allocate bounce buffer for 3D caps.\n");
	100	return -ENOMEM;
	101	}
	102
	103	fifo_mem = dev_priv->mmio_virt;
	104	memcpy_fromio(bounce, &fifo_mem[SVGA_FIFO_3D_CAPS], size);
	105
	106	ret = copy_to_user(buffer, bounce, size);
	107	vfree(bounce);
	108
	109	if (unlikely(ret != 0))
	110	DRM_ERROR("Failed to report 3D caps info.\n");
	111
	112	return ret;
	113	}
2fcd5a73 JB	114
	115	int vmw_present_ioctl(struct drm_device dev, void data,
	116	struct drm_file *file_priv)
	117	{
	118	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	119	struct vmw_private *dev_priv = vmw_priv(dev);
	120	struct drm_vmw_present_arg *arg =
	121	(struct drm_vmw_present_arg *)data;
	122	struct vmw_surface *surface;
	123	struct vmw_master *vmaster = vmw_master(file_priv->master);
	124	struct drm_vmw_rect __user *clips_ptr;
	125	struct drm_vmw_rect *clips = NULL;
	126	struct drm_mode_object *obj;
	127	struct vmw_framebuffer *vfb;
	128	uint32_t num_clips;
	129	int ret;
	130
	131	num_clips = arg->num_clips;
	132	clips_ptr = (struct drm_vmw_rect *)(unsigned long)arg->clips_ptr;
	133
	134	if (unlikely(num_clips == 0))
	135	return 0;
	136
	137	if (clips_ptr == NULL) {
	138	DRM_ERROR("Variable clips_ptr must be specified.\n");
	139	ret = -EINVAL;
	140	goto out_clips;
	141	}
	142
	143	clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
	144	if (clips == NULL) {
	145	DRM_ERROR("Failed to allocate clip rect list.\n");
	146	ret = -ENOMEM;
	147	goto out_clips;
	148	}
	149
	150	ret = copy_from_user(clips, clips_ptr, num_clips * sizeof(*clips));
	151	if (ret) {
	152	DRM_ERROR("Failed to copy clip rects from userspace.\n");
d2c184fb	153	ret = -EFAULT;
2fcd5a73 JB	154	goto out_no_copy;
	155	}
	156
	157	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
	158	if (unlikely(ret != 0)) {
	159	ret = -ERESTARTSYS;
	160	goto out_no_mode_mutex;
	161	}
	162
	163	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
	164	if (!obj) {
	165	DRM_ERROR("Invalid framebuffer id.\n");
	166	ret = -EINVAL;
	167	goto out_no_fb;
	168	}
	169
	170	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
	171	if (!vfb->dmabuf) {
	172	DRM_ERROR("Framebuffer not dmabuf backed.\n");
	173	ret = -EINVAL;
	174	goto out_no_fb;
	175	}
	176
	177	ret = ttm_read_lock(&vmaster->lock, true);
	178	if (unlikely(ret != 0))
	179	goto out_no_ttm_lock;
	180
	181	ret = vmw_user_surface_lookup_handle(dev_priv, tfile, arg->sid,
	182	&surface);
	183	if (ret)
	184	goto out_no_surface;
	185
	186	ret = vmw_kms_present(dev_priv, file_priv,
	187	vfb, surface, arg->sid,
	188	arg->dest_x, arg->dest_y,
	189	clips, num_clips);
	190
	191	/* vmw_user_surface_lookup takes one ref so does new_fb */
	192	vmw_surface_unreference(&surface);
	193
	194	out_no_surface:
	195	ttm_read_unlock(&vmaster->lock);
	196	out_no_ttm_lock:
	197	out_no_fb:
	198	mutex_unlock(&dev->mode_config.mutex);
	199	out_no_mode_mutex:
	200	out_no_copy:
	201	kfree(clips);
	202	out_clips:
	203	return ret;
	204	}
	205
	206	int vmw_present_readback_ioctl(struct drm_device dev, void data,
	207	struct drm_file *file_priv)
	208	{
	209	struct vmw_private *dev_priv = vmw_priv(dev);
	210	struct drm_vmw_present_readback_arg *arg =
	211	(struct drm_vmw_present_readback_arg *)data;
	212	struct drm_vmw_fence_rep __user *user_fence_rep =
	213	(struct drm_vmw_fence_rep __user *)
	214	(unsigned long)arg->fence_rep;
	215	struct vmw_master *vmaster = vmw_master(file_priv->master);
	216	struct drm_vmw_rect __user *clips_ptr;
	217	struct drm_vmw_rect *clips = NULL;
218	struct drm_mode_object *obj;
219	struct vmw_framebuffer *vfb;
220	uint32_t num_clips;
221	int ret;
222
223	num_clips = arg->num_clips;
224	clips_ptr = (struct drm_vmw_rect *)(unsigned long)arg->clips_ptr;
225
226	if (unlikely(num_clips == 0))
227	return 0;
228
229	if (clips_ptr == NULL) {
230	DRM_ERROR("Argument clips_ptr must be specified.\n");
231	ret = -EINVAL;
232	goto out_clips;
233	}
234
235	clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL);
236	if (clips == NULL) {
237	DRM_ERROR("Failed to allocate clip rect list.\n");
238	ret = -ENOMEM;
239	goto out_clips;
240	}
241
242	ret = copy_from_user(clips, clips_ptr, num_clips * sizeof(*clips));
243	if (ret) {
244	DRM_ERROR("Failed to copy clip rects from userspace.\n");
d2c184fb	245	ret = -EFAULT;
2fcd5a73 JB	246	goto out_no_copy;
	247	}
	248
	249	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
	250	if (unlikely(ret != 0)) {
	251	ret = -ERESTARTSYS;
	252	goto out_no_mode_mutex;
	253	}
	254
	255	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
	256	if (!obj) {
	257	DRM_ERROR("Invalid framebuffer id.\n");
	258	ret = -EINVAL;
	259	goto out_no_fb;
	260	}
	261
	262	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
	263	if (!vfb->dmabuf) {
	264	DRM_ERROR("Framebuffer not dmabuf backed.\n");
	265	ret = -EINVAL;
	266	goto out_no_fb;
	267	}
	268
	269	ret = ttm_read_lock(&vmaster->lock, true);
	270	if (unlikely(ret != 0))
	271	goto out_no_ttm_lock;
	272
	273	ret = vmw_kms_readback(dev_priv, file_priv,
	274	vfb, user_fence_rep,
	275	clips, num_clips);
	276
	277	ttm_read_unlock(&vmaster->lock);
	278	out_no_ttm_lock:
	279	out_no_fb:
	280	mutex_unlock(&dev->mode_config.mutex);
	281	out_no_mode_mutex:
	282	out_no_copy:
	283	kfree(clips);
	284	out_clips:
	285	return ret;
	286	}
5438ae88 TH	287
	288
	289	/**
	290	* vmw_fops_poll - wrapper around the drm_poll function
	291	*
	292	* @filp: See the linux fops poll documentation.
	293	* @wait: See the linux fops poll documentation.
	294	*
	295	* Wrapper around the drm_poll function that makes sure the device is
	296	* processing the fifo if drm_poll decides to wait.
	297	*/
	298	unsigned int vmw_fops_poll(struct file filp, struct poll_table_struct wait)
	299	{
	300	struct drm_file *file_priv = filp->private_data;
	301	struct vmw_private *dev_priv =
	302	vmw_priv(file_priv->minor->dev);
	303
	304	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
	305	return drm_poll(filp, wait);
	306	}
	307
	308
	309	/**
	310	* vmw_fops_read - wrapper around the drm_read function
	311	*
	312	* @filp: See the linux fops read documentation.
	313	* @buffer: See the linux fops read documentation.
	314	* @count: See the linux fops read documentation.
	315	* offset: See the linux fops read documentation.
	316	*
	317	* Wrapper around the drm_read function that makes sure the device is
	318	* processing the fifo if drm_read decides to wait.
	319	*/
	320	ssize_t vmw_fops_read(struct file filp, char __user buffer,
	321	size_t count, loff_t *offset)
	322	{
	323	struct drm_file *file_priv = filp->private_data;
	324	struct vmw_private *dev_priv =
	325	vmw_priv(file_priv->minor->dev);
	326
	327	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);
	328	return drm_read(filp, buffer, count, offset);
	329	}