xref: /linux/drivers/gpu/drm/gud/gud_drv.c (revision fb7399cf2d0b33825b8039f95c45395c7deba25c)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright 2020 Noralf Trønnes
4  */
5 
6 #include <linux/dma-buf.h>
7 #include <linux/dma-mapping.h>
8 #include <linux/lz4.h>
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/string_helpers.h>
12 #include <linux/usb.h>
13 #include <linux/vmalloc.h>
14 #include <linux/workqueue.h>
15 
16 #include <drm/clients/drm_client_setup.h>
17 #include <drm/drm_atomic_helper.h>
18 #include <drm/drm_blend.h>
19 #include <drm/drm_damage_helper.h>
20 #include <drm/drm_debugfs.h>
21 #include <drm/drm_drv.h>
22 #include <drm/drm_fbdev_shmem.h>
23 #include <drm/drm_fourcc.h>
24 #include <drm/drm_gem_atomic_helper.h>
25 #include <drm/drm_gem_framebuffer_helper.h>
26 #include <drm/drm_gem_shmem_helper.h>
27 #include <drm/drm_managed.h>
28 #include <drm/drm_print.h>
29 #include <drm/drm_probe_helper.h>
30 #include <drm/drm_simple_kms_helper.h>
31 #include <drm/gud.h>
32 
33 #include "gud_internal.h"
34 
35 /* Only used internally */
36 static const struct drm_format_info gud_drm_format_r1 = {
37 	.format = GUD_DRM_FORMAT_R1,
38 	.num_planes = 1,
39 	.char_per_block = { 1, 0, 0 },
40 	.block_w = { 8, 0, 0 },
41 	.block_h = { 1, 0, 0 },
42 	.hsub = 1,
43 	.vsub = 1,
44 };
45 
46 static const struct drm_format_info gud_drm_format_xrgb1111 = {
47 	.format = GUD_DRM_FORMAT_XRGB1111,
48 	.num_planes = 1,
49 	.char_per_block = { 1, 0, 0 },
50 	.block_w = { 2, 0, 0 },
51 	.block_h = { 1, 0, 0 },
52 	.hsub = 1,
53 	.vsub = 1,
54 };
55 
56 static int gud_usb_control_msg(struct usb_interface *intf, bool in,
57 			       u8 request, u16 value, void *buf, size_t len)
58 {
59 	u8 requesttype = USB_TYPE_VENDOR | USB_RECIP_INTERFACE;
60 	u8 ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
61 	struct usb_device *usb = interface_to_usbdev(intf);
62 	unsigned int pipe;
63 
64 	if (len && !buf)
65 		return -EINVAL;
66 
67 	if (in) {
68 		pipe = usb_rcvctrlpipe(usb, 0);
69 		requesttype |= USB_DIR_IN;
70 	} else {
71 		pipe = usb_sndctrlpipe(usb, 0);
72 		requesttype |= USB_DIR_OUT;
73 	}
74 
75 	return usb_control_msg(usb, pipe, request, requesttype, value,
76 			       ifnum, buf, len, USB_CTRL_GET_TIMEOUT);
77 }
78 
79 static int gud_get_display_descriptor(struct usb_interface *intf,
80 				      struct gud_display_descriptor_req *desc)
81 {
82 	void *buf;
83 	int ret;
84 
85 	buf = kmalloc(sizeof(*desc), GFP_KERNEL);
86 	if (!buf)
87 		return -ENOMEM;
88 
89 	ret = gud_usb_control_msg(intf, true, GUD_REQ_GET_DESCRIPTOR, 0, buf, sizeof(*desc));
90 	memcpy(desc, buf, sizeof(*desc));
91 	kfree(buf);
92 	if (ret < 0)
93 		return ret;
94 	if (ret != sizeof(*desc))
95 		return -EIO;
96 
97 	if (desc->magic != le32_to_cpu(GUD_DISPLAY_MAGIC))
98 		return -ENODATA;
99 
100 	DRM_DEV_DEBUG_DRIVER(&intf->dev,
101 			     "version=%u flags=0x%x compression=0x%x max_buffer_size=%u\n",
102 			     desc->version, le32_to_cpu(desc->flags), desc->compression,
103 			     le32_to_cpu(desc->max_buffer_size));
104 
105 	if (!desc->version || !desc->max_width || !desc->max_height ||
106 	    le32_to_cpu(desc->min_width) > le32_to_cpu(desc->max_width) ||
107 	    le32_to_cpu(desc->min_height) > le32_to_cpu(desc->max_height))
108 		return -EINVAL;
109 
110 	return 0;
111 }
112 
113 static int gud_status_to_errno(u8 status)
114 {
115 	switch (status) {
116 	case GUD_STATUS_OK:
117 		return 0;
118 	case GUD_STATUS_BUSY:
119 		return -EBUSY;
120 	case GUD_STATUS_REQUEST_NOT_SUPPORTED:
121 		return -EOPNOTSUPP;
122 	case GUD_STATUS_PROTOCOL_ERROR:
123 		return -EPROTO;
124 	case GUD_STATUS_INVALID_PARAMETER:
125 		return -EINVAL;
126 	case GUD_STATUS_ERROR:
127 		return -EREMOTEIO;
128 	default:
129 		return -EREMOTEIO;
130 	}
131 }
132 
133 static int gud_usb_get_status(struct usb_interface *intf)
134 {
135 	int ret, status = -EIO;
136 	u8 *buf;
137 
138 	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
139 	if (!buf)
140 		return -ENOMEM;
141 
142 	ret = gud_usb_control_msg(intf, true, GUD_REQ_GET_STATUS, 0, buf, sizeof(*buf));
143 	if (ret == sizeof(*buf))
144 		status = gud_status_to_errno(*buf);
145 	kfree(buf);
146 
147 	if (ret < 0)
148 		return ret;
149 
150 	return status;
151 }
152 
153 static int gud_usb_transfer(struct gud_device *gdrm, bool in, u8 request, u16 index,
154 			    void *buf, size_t len)
155 {
156 	struct usb_interface *intf = to_usb_interface(gdrm->drm.dev);
157 	int idx, ret;
158 
159 	drm_dbg(&gdrm->drm, "%s: request=0x%x index=%u len=%zu\n",
160 		in ? "get" : "set", request, index, len);
161 
162 	if (!drm_dev_enter(&gdrm->drm, &idx))
163 		return -ENODEV;
164 
165 	mutex_lock(&gdrm->ctrl_lock);
166 
167 	ret = gud_usb_control_msg(intf, in, request, index, buf, len);
168 	if (ret == -EPIPE || ((gdrm->flags & GUD_DISPLAY_FLAG_STATUS_ON_SET) && !in && ret >= 0)) {
169 		int status;
170 
171 		status = gud_usb_get_status(intf);
172 		if (status < 0) {
173 			ret = status;
174 		} else if (ret < 0) {
175 			dev_err_once(gdrm->drm.dev,
176 				     "Unexpected status OK for failed transfer\n");
177 			ret = -EPIPE;
178 		}
179 	}
180 
181 	if (ret < 0) {
182 		drm_dbg(&gdrm->drm, "ret=%d\n", ret);
183 		gdrm->stats_num_errors++;
184 	}
185 
186 	mutex_unlock(&gdrm->ctrl_lock);
187 	drm_dev_exit(idx);
188 
189 	return ret;
190 }
191 
192 /*
193  * @buf cannot be allocated on the stack.
194  * Returns number of bytes received or negative error code on failure.
195  */
196 int gud_usb_get(struct gud_device *gdrm, u8 request, u16 index, void *buf, size_t max_len)
197 {
198 	return gud_usb_transfer(gdrm, true, request, index, buf, max_len);
199 }
200 
201 /*
202  * @buf can be allocated on the stack or NULL.
203  * Returns zero on success or negative error code on failure.
204  */
205 int gud_usb_set(struct gud_device *gdrm, u8 request, u16 index, void *buf, size_t len)
206 {
207 	void *trbuf = NULL;
208 	int ret;
209 
210 	if (buf && len) {
211 		trbuf = kmemdup(buf, len, GFP_KERNEL);
212 		if (!trbuf)
213 			return -ENOMEM;
214 	}
215 
216 	ret = gud_usb_transfer(gdrm, false, request, index, trbuf, len);
217 	kfree(trbuf);
218 	if (ret < 0)
219 		return ret;
220 
221 	return ret != len ? -EIO : 0;
222 }
223 
224 /*
225  * @val can be allocated on the stack.
226  * Returns zero on success or negative error code on failure.
227  */
228 int gud_usb_get_u8(struct gud_device *gdrm, u8 request, u16 index, u8 *val)
229 {
230 	u8 *buf;
231 	int ret;
232 
233 	buf = kmalloc(sizeof(*val), GFP_KERNEL);
234 	if (!buf)
235 		return -ENOMEM;
236 
237 	ret = gud_usb_get(gdrm, request, index, buf, sizeof(*val));
238 	*val = *buf;
239 	kfree(buf);
240 	if (ret < 0)
241 		return ret;
242 
243 	return ret != sizeof(*val) ? -EIO : 0;
244 }
245 
246 /* Returns zero on success or negative error code on failure. */
247 int gud_usb_set_u8(struct gud_device *gdrm, u8 request, u8 val)
248 {
249 	return gud_usb_set(gdrm, request, 0, &val, sizeof(val));
250 }
251 
252 static int gud_get_properties(struct gud_device *gdrm)
253 {
254 	struct gud_property_req *properties;
255 	unsigned int i, num_properties;
256 	int ret;
257 
258 	properties = kcalloc(GUD_PROPERTIES_MAX_NUM, sizeof(*properties), GFP_KERNEL);
259 	if (!properties)
260 		return -ENOMEM;
261 
262 	ret = gud_usb_get(gdrm, GUD_REQ_GET_PROPERTIES, 0,
263 			  properties, GUD_PROPERTIES_MAX_NUM * sizeof(*properties));
264 	if (ret <= 0)
265 		goto out;
266 	if (ret % sizeof(*properties)) {
267 		ret = -EIO;
268 		goto out;
269 	}
270 
271 	num_properties = ret / sizeof(*properties);
272 	ret = 0;
273 
274 	gdrm->properties = drmm_kcalloc(&gdrm->drm, num_properties, sizeof(*gdrm->properties),
275 					GFP_KERNEL);
276 	if (!gdrm->properties) {
277 		ret = -ENOMEM;
278 		goto out;
279 	}
280 
281 	for (i = 0; i < num_properties; i++) {
282 		u16 prop = le16_to_cpu(properties[i].prop);
283 		u64 val = le64_to_cpu(properties[i].val);
284 
285 		switch (prop) {
286 		case GUD_PROPERTY_ROTATION:
287 			/*
288 			 * DRM UAPI matches the protocol so use the value directly,
289 			 * but mask out any additions on future devices.
290 			 */
291 			val &= GUD_ROTATION_MASK;
292 			ret = drm_plane_create_rotation_property(&gdrm->pipe.plane,
293 								 DRM_MODE_ROTATE_0, val);
294 			break;
295 		default:
296 			/* New ones might show up in future devices, skip those we don't know. */
297 			drm_dbg(&gdrm->drm, "Ignoring unknown property: %u\n", prop);
298 			continue;
299 		}
300 
301 		if (ret)
302 			goto out;
303 
304 		gdrm->properties[gdrm->num_properties++] = prop;
305 	}
306 out:
307 	kfree(properties);
308 
309 	return ret;
310 }
311 
312 static int gud_stats_debugfs(struct seq_file *m, void *data)
313 {
314 	struct drm_debugfs_entry *entry = m->private;
315 	struct gud_device *gdrm = to_gud_device(entry->dev);
316 	char buf[10];
317 
318 	string_get_size(gdrm->bulk_len, 1, STRING_UNITS_2, buf, sizeof(buf));
319 	seq_printf(m, "Max buffer size: %s\n", buf);
320 	seq_printf(m, "Number of errors:  %u\n", gdrm->stats_num_errors);
321 
322 	seq_puts(m, "Compression:      ");
323 	if (gdrm->compression & GUD_COMPRESSION_LZ4)
324 		seq_puts(m, " lz4");
325 	if (!gdrm->compression)
326 		seq_puts(m, " none");
327 	seq_puts(m, "\n");
328 
329 	if (gdrm->compression) {
330 		u64 remainder;
331 		u64 ratio = div64_u64_rem(gdrm->stats_length, gdrm->stats_actual_length,
332 					  &remainder);
333 		u64 ratio_frac = div64_u64(remainder * 10, gdrm->stats_actual_length);
334 
335 		seq_printf(m, "Compression ratio: %llu.%llu\n", ratio, ratio_frac);
336 	}
337 
338 	return 0;
339 }
340 
341 static const struct drm_simple_display_pipe_funcs gud_pipe_funcs = {
342 	.check      = gud_pipe_check,
343 	.update	    = gud_pipe_update,
344 	DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS
345 };
346 
347 static const struct drm_mode_config_funcs gud_mode_config_funcs = {
348 	.fb_create = drm_gem_fb_create_with_dirty,
349 	.atomic_check = drm_atomic_helper_check,
350 	.atomic_commit = drm_atomic_helper_commit,
351 };
352 
353 static const u64 gud_pipe_modifiers[] = {
354 	DRM_FORMAT_MOD_LINEAR,
355 	DRM_FORMAT_MOD_INVALID
356 };
357 
358 DEFINE_DRM_GEM_FOPS(gud_fops);
359 
360 static const struct drm_driver gud_drm_driver = {
361 	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
362 	.fops			= &gud_fops,
363 	DRM_GEM_SHMEM_DRIVER_OPS,
364 	DRM_FBDEV_SHMEM_DRIVER_OPS,
365 
366 	.name			= "gud",
367 	.desc			= "Generic USB Display",
368 	.major			= 1,
369 	.minor			= 0,
370 };
371 
372 static int gud_alloc_bulk_buffer(struct gud_device *gdrm)
373 {
374 	unsigned int i, num_pages;
375 	struct page **pages;
376 	void *ptr;
377 	int ret;
378 
379 	gdrm->bulk_buf = vmalloc_32(gdrm->bulk_len);
380 	if (!gdrm->bulk_buf)
381 		return -ENOMEM;
382 
383 	num_pages = DIV_ROUND_UP(gdrm->bulk_len, PAGE_SIZE);
384 	pages = kmalloc_array(num_pages, sizeof(struct page *), GFP_KERNEL);
385 	if (!pages)
386 		return -ENOMEM;
387 
388 	for (i = 0, ptr = gdrm->bulk_buf; i < num_pages; i++, ptr += PAGE_SIZE)
389 		pages[i] = vmalloc_to_page(ptr);
390 
391 	ret = sg_alloc_table_from_pages(&gdrm->bulk_sgt, pages, num_pages,
392 					0, gdrm->bulk_len, GFP_KERNEL);
393 	kfree(pages);
394 
395 	return ret;
396 }
397 
398 static void gud_free_buffers_and_mutex(void *data)
399 {
400 	struct gud_device *gdrm = data;
401 
402 	vfree(gdrm->compress_buf);
403 	gdrm->compress_buf = NULL;
404 	sg_free_table(&gdrm->bulk_sgt);
405 	vfree(gdrm->bulk_buf);
406 	gdrm->bulk_buf = NULL;
407 	mutex_destroy(&gdrm->ctrl_lock);
408 }
409 
410 static int gud_probe(struct usb_interface *intf, const struct usb_device_id *id)
411 {
412 	const struct drm_format_info *xrgb8888_emulation_format = NULL;
413 	bool rgb565_supported = false, xrgb8888_supported = false;
414 	unsigned int num_formats_dev, num_formats = 0;
415 	struct usb_endpoint_descriptor *bulk_out;
416 	struct gud_display_descriptor_req desc;
417 	struct device *dev = &intf->dev;
418 	size_t max_buffer_size = 0;
419 	struct gud_device *gdrm;
420 	struct drm_device *drm;
421 	struct device *dma_dev;
422 	u8 *formats_dev;
423 	u32 *formats;
424 	int ret, i;
425 
426 	ret = usb_find_bulk_out_endpoint(intf->cur_altsetting, &bulk_out);
427 	if (ret)
428 		return ret;
429 
430 	ret = gud_get_display_descriptor(intf, &desc);
431 	if (ret) {
432 		DRM_DEV_DEBUG_DRIVER(dev, "Not a display interface: ret=%d\n", ret);
433 		return -ENODEV;
434 	}
435 
436 	if (desc.version > 1) {
437 		dev_err(dev, "Protocol version %u is not supported\n", desc.version);
438 		return -ENODEV;
439 	}
440 
441 	gdrm = devm_drm_dev_alloc(dev, &gud_drm_driver, struct gud_device, drm);
442 	if (IS_ERR(gdrm))
443 		return PTR_ERR(gdrm);
444 
445 	drm = &gdrm->drm;
446 	drm->mode_config.funcs = &gud_mode_config_funcs;
447 	ret = drmm_mode_config_init(drm);
448 	if (ret)
449 		return ret;
450 
451 	gdrm->flags = le32_to_cpu(desc.flags);
452 	gdrm->compression = desc.compression & GUD_COMPRESSION_LZ4;
453 
454 	if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE && gdrm->compression)
455 		return -EINVAL;
456 
457 	mutex_init(&gdrm->ctrl_lock);
458 	mutex_init(&gdrm->damage_lock);
459 	INIT_WORK(&gdrm->work, gud_flush_work);
460 	gud_clear_damage(gdrm);
461 
462 	ret = devm_add_action(dev, gud_free_buffers_and_mutex, gdrm);
463 	if (ret)
464 		return ret;
465 
466 	drm->mode_config.min_width = le32_to_cpu(desc.min_width);
467 	drm->mode_config.max_width = le32_to_cpu(desc.max_width);
468 	drm->mode_config.min_height = le32_to_cpu(desc.min_height);
469 	drm->mode_config.max_height = le32_to_cpu(desc.max_height);
470 
471 	formats_dev = devm_kmalloc(dev, GUD_FORMATS_MAX_NUM, GFP_KERNEL);
472 	/* Add room for emulated XRGB8888 */
473 	formats = devm_kmalloc_array(dev, GUD_FORMATS_MAX_NUM + 1, sizeof(*formats), GFP_KERNEL);
474 	if (!formats_dev || !formats)
475 		return -ENOMEM;
476 
477 	ret = gud_usb_get(gdrm, GUD_REQ_GET_FORMATS, 0, formats_dev, GUD_FORMATS_MAX_NUM);
478 	if (ret < 0)
479 		return ret;
480 
481 	num_formats_dev = ret;
482 	for (i = 0; i < num_formats_dev; i++) {
483 		const struct drm_format_info *info;
484 		size_t fmt_buf_size;
485 		u32 format;
486 
487 		format = gud_to_fourcc(formats_dev[i]);
488 		if (!format) {
489 			drm_dbg(drm, "Unsupported format: 0x%02x\n", formats_dev[i]);
490 			continue;
491 		}
492 
493 		if (format == GUD_DRM_FORMAT_R1)
494 			info = &gud_drm_format_r1;
495 		else if (format == GUD_DRM_FORMAT_XRGB1111)
496 			info = &gud_drm_format_xrgb1111;
497 		else
498 			info = drm_format_info(format);
499 
500 		switch (format) {
501 		case GUD_DRM_FORMAT_R1:
502 			fallthrough;
503 		case DRM_FORMAT_R8:
504 			fallthrough;
505 		case GUD_DRM_FORMAT_XRGB1111:
506 			fallthrough;
507 		case DRM_FORMAT_RGB332:
508 			fallthrough;
509 		case DRM_FORMAT_RGB888:
510 			if (!xrgb8888_emulation_format)
511 				xrgb8888_emulation_format = info;
512 			break;
513 		case DRM_FORMAT_RGB565:
514 			rgb565_supported = true;
515 			if (!xrgb8888_emulation_format)
516 				xrgb8888_emulation_format = info;
517 			break;
518 		case DRM_FORMAT_XRGB8888:
519 			xrgb8888_supported = true;
520 			break;
521 		}
522 
523 		fmt_buf_size = drm_format_info_min_pitch(info, 0, drm->mode_config.max_width) *
524 			       drm->mode_config.max_height;
525 		max_buffer_size = max(max_buffer_size, fmt_buf_size);
526 
527 		if (format == GUD_DRM_FORMAT_R1 || format == GUD_DRM_FORMAT_XRGB1111)
528 			continue; /* Internal not for userspace */
529 
530 		formats[num_formats++] = format;
531 	}
532 
533 	if (!num_formats && !xrgb8888_emulation_format) {
534 		dev_err(dev, "No supported pixel formats found\n");
535 		return -EINVAL;
536 	}
537 
538 	/* Prefer speed over color depth */
539 	if (rgb565_supported)
540 		drm->mode_config.preferred_depth = 16;
541 
542 	if (!xrgb8888_supported && xrgb8888_emulation_format) {
543 		gdrm->xrgb8888_emulation_format = xrgb8888_emulation_format;
544 		formats[num_formats++] = DRM_FORMAT_XRGB8888;
545 	}
546 
547 	if (desc.max_buffer_size)
548 		max_buffer_size = le32_to_cpu(desc.max_buffer_size);
549 	/* Prevent a misbehaving device from allocating loads of RAM. 4096x4096@XRGB8888 = 64 MB */
550 	if (max_buffer_size > SZ_64M)
551 		max_buffer_size = SZ_64M;
552 
553 	gdrm->bulk_pipe = usb_sndbulkpipe(interface_to_usbdev(intf), usb_endpoint_num(bulk_out));
554 	gdrm->bulk_len = max_buffer_size;
555 
556 	ret = gud_alloc_bulk_buffer(gdrm);
557 	if (ret)
558 		return ret;
559 
560 	if (gdrm->compression & GUD_COMPRESSION_LZ4) {
561 		gdrm->lz4_comp_mem = devm_kmalloc(dev, LZ4_MEM_COMPRESS, GFP_KERNEL);
562 		if (!gdrm->lz4_comp_mem)
563 			return -ENOMEM;
564 
565 		gdrm->compress_buf = vmalloc(gdrm->bulk_len);
566 		if (!gdrm->compress_buf)
567 			return -ENOMEM;
568 	}
569 
570 	ret = drm_simple_display_pipe_init(drm, &gdrm->pipe, &gud_pipe_funcs,
571 					   formats, num_formats,
572 					   gud_pipe_modifiers, NULL);
573 	if (ret)
574 		return ret;
575 
576 	devm_kfree(dev, formats);
577 	devm_kfree(dev, formats_dev);
578 
579 	ret = gud_get_properties(gdrm);
580 	if (ret) {
581 		dev_err(dev, "Failed to get properties (error=%d)\n", ret);
582 		return ret;
583 	}
584 
585 	drm_plane_enable_fb_damage_clips(&gdrm->pipe.plane);
586 
587 	ret = gud_get_connectors(gdrm);
588 	if (ret) {
589 		dev_err(dev, "Failed to get connectors (error=%d)\n", ret);
590 		return ret;
591 	}
592 
593 	drm_mode_config_reset(drm);
594 
595 	usb_set_intfdata(intf, gdrm);
596 
597 	dma_dev = usb_intf_get_dma_device(intf);
598 	if (dma_dev) {
599 		drm_dev_set_dma_dev(drm, dma_dev);
600 		put_device(dma_dev);
601 	} else {
602 		dev_warn(dev, "buffer sharing not supported"); /* not an error */
603 	}
604 
605 	drm_debugfs_add_file(drm, "stats", gud_stats_debugfs, NULL);
606 
607 	ret = drm_dev_register(drm, 0);
608 	if (ret)
609 		return ret;
610 
611 	drm_kms_helper_poll_init(drm);
612 
613 	drm_client_setup(drm, NULL);
614 
615 	return 0;
616 }
617 
618 static void gud_disconnect(struct usb_interface *interface)
619 {
620 	struct gud_device *gdrm = usb_get_intfdata(interface);
621 	struct drm_device *drm = &gdrm->drm;
622 
623 	drm_dbg(drm, "%s:\n", __func__);
624 
625 	drm_kms_helper_poll_fini(drm);
626 	drm_dev_unplug(drm);
627 	drm_atomic_helper_shutdown(drm);
628 }
629 
630 static int gud_suspend(struct usb_interface *intf, pm_message_t message)
631 {
632 	struct gud_device *gdrm = usb_get_intfdata(intf);
633 
634 	return drm_mode_config_helper_suspend(&gdrm->drm);
635 }
636 
637 static int gud_resume(struct usb_interface *intf)
638 {
639 	struct gud_device *gdrm = usb_get_intfdata(intf);
640 
641 	drm_mode_config_helper_resume(&gdrm->drm);
642 
643 	return 0;
644 }
645 
646 static const struct usb_device_id gud_id_table[] = {
647 	{ USB_DEVICE_INTERFACE_CLASS(0x1d50, 0x614d, USB_CLASS_VENDOR_SPEC) },
648 	{ USB_DEVICE_INTERFACE_CLASS(0x16d0, 0x10a9, USB_CLASS_VENDOR_SPEC) },
649 	{ }
650 };
651 
652 MODULE_DEVICE_TABLE(usb, gud_id_table);
653 
654 static struct usb_driver gud_usb_driver = {
655 	.name		= "gud",
656 	.probe		= gud_probe,
657 	.disconnect	= gud_disconnect,
658 	.id_table	= gud_id_table,
659 	.suspend	= gud_suspend,
660 	.resume		= gud_resume,
661 	.reset_resume	= gud_resume,
662 };
663 
664 module_usb_driver(gud_usb_driver);
665 
666 MODULE_AUTHOR("Noralf Trønnes");
667 MODULE_DESCRIPTION("GUD USB Display driver");
668 MODULE_LICENSE("Dual MIT/GPL");
669