xref: /openbmc/linux/drivers/gpu/drm/udl/udl_modeset.c (revision 1edd0337)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Red Hat
4  *
5  * based in parts on udlfb.c:
6  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
7  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
8  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
9  */
10 
11 #include <linux/bitfield.h>
12 
13 #include <drm/drm_atomic.h>
14 #include <drm/drm_atomic_helper.h>
15 #include <drm/drm_damage_helper.h>
16 #include <drm/drm_drv.h>
17 #include <drm/drm_edid.h>
18 #include <drm/drm_fourcc.h>
19 #include <drm/drm_gem_atomic_helper.h>
20 #include <drm/drm_gem_framebuffer_helper.h>
21 #include <drm/drm_gem_shmem_helper.h>
22 #include <drm/drm_modeset_helper_vtables.h>
23 #include <drm/drm_plane_helper.h>
24 #include <drm/drm_probe_helper.h>
25 #include <drm/drm_vblank.h>
26 
27 #include "udl_drv.h"
28 #include "udl_proto.h"
29 
30 /*
31  * All DisplayLink bulk operations start with 0xaf (UDL_MSG_BULK), followed by
32  * a specific command code. All operations are written to a command buffer, which
33  * the driver sends to the device.
34  */
35 static char *udl_set_register(char *buf, u8 reg, u8 val)
36 {
37 	*buf++ = UDL_MSG_BULK;
38 	*buf++ = UDL_CMD_WRITEREG;
39 	*buf++ = reg;
40 	*buf++ = val;
41 
42 	return buf;
43 }
44 
45 static char *udl_vidreg_lock(char *buf)
46 {
47 	return udl_set_register(buf, UDL_REG_VIDREG, UDL_VIDREG_LOCK);
48 }
49 
50 static char *udl_vidreg_unlock(char *buf)
51 {
52 	return udl_set_register(buf, UDL_REG_VIDREG, UDL_VIDREG_UNLOCK);
53 }
54 
55 static char *udl_set_blank_mode(char *buf, u8 mode)
56 {
57 	return udl_set_register(buf, UDL_REG_BLANKMODE, mode);
58 }
59 
60 static char *udl_set_color_depth(char *buf, u8 selection)
61 {
62 	return udl_set_register(buf, UDL_REG_COLORDEPTH, selection);
63 }
64 
65 static char *udl_set_base16bpp(char *buf, u32 base)
66 {
67 	/* the base pointer is 24 bits wide, 0x20 is hi byte. */
68 	u8 reg20 = FIELD_GET(UDL_BASE_ADDR2_MASK, base);
69 	u8 reg21 = FIELD_GET(UDL_BASE_ADDR1_MASK, base);
70 	u8 reg22 = FIELD_GET(UDL_BASE_ADDR0_MASK, base);
71 
72 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR2, reg20);
73 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR1, reg21);
74 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR0, reg22);
75 
76 	return buf;
77 }
78 
79 /*
80  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
81  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
82  */
83 static char *udl_set_base8bpp(char *buf, u32 base)
84 {
85 	/* the base pointer is 24 bits wide, 0x26 is hi byte. */
86 	u8 reg26 = FIELD_GET(UDL_BASE_ADDR2_MASK, base);
87 	u8 reg27 = FIELD_GET(UDL_BASE_ADDR1_MASK, base);
88 	u8 reg28 = FIELD_GET(UDL_BASE_ADDR0_MASK, base);
89 
90 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR2, reg26);
91 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR1, reg27);
92 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR0, reg28);
93 
94 	return buf;
95 }
96 
97 static char *udl_set_register_16(char *wrptr, u8 reg, u16 value)
98 {
99 	wrptr = udl_set_register(wrptr, reg, value >> 8);
100 	return udl_set_register(wrptr, reg+1, value);
101 }
102 
103 /*
104  * This is kind of weird because the controller takes some
105  * register values in a different byte order than other registers.
106  */
107 static char *udl_set_register_16be(char *wrptr, u8 reg, u16 value)
108 {
109 	wrptr = udl_set_register(wrptr, reg, value);
110 	return udl_set_register(wrptr, reg+1, value >> 8);
111 }
112 
113 /*
114  * LFSR is linear feedback shift register. The reason we have this is
115  * because the display controller needs to minimize the clock depth of
116  * various counters used in the display path. So this code reverses the
117  * provided value into the lfsr16 value by counting backwards to get
118  * the value that needs to be set in the hardware comparator to get the
119  * same actual count. This makes sense once you read above a couple of
120  * times and think about it from a hardware perspective.
121  */
122 static u16 udl_lfsr16(u16 actual_count)
123 {
124 	u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
125 
126 	while (actual_count--) {
127 		lv =	 ((lv << 1) |
128 			(((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
129 			& 0xFFFF;
130 	}
131 
132 	return (u16) lv;
133 }
134 
135 /*
136  * This does LFSR conversion on the value that is to be written.
137  * See LFSR explanation above for more detail.
138  */
139 static char *udl_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
140 {
141 	return udl_set_register_16(wrptr, reg, udl_lfsr16(value));
142 }
143 
144 /*
145  * Takes a DRM display mode and converts it into the DisplayLink
146  * equivalent register commands.
147  */
148 static char *udl_set_display_mode(char *buf, struct drm_display_mode *mode)
149 {
150 	u16 reg01 = mode->crtc_htotal - mode->crtc_hsync_start;
151 	u16 reg03 = reg01 + mode->crtc_hdisplay;
152 	u16 reg05 = mode->crtc_vtotal - mode->crtc_vsync_start;
153 	u16 reg07 = reg05 + mode->crtc_vdisplay;
154 	u16 reg09 = mode->crtc_htotal - 1;
155 	u16 reg0b = 1; /* libdlo hardcodes hsync start to 1 */
156 	u16 reg0d = mode->crtc_hsync_end - mode->crtc_hsync_start + 1;
157 	u16 reg0f = mode->hdisplay;
158 	u16 reg11 = mode->crtc_vtotal;
159 	u16 reg13 = 0; /* libdlo hardcodes vsync start to 0 */
160 	u16 reg15 = mode->crtc_vsync_end - mode->crtc_vsync_start;
161 	u16 reg17 = mode->crtc_vdisplay;
162 	u16 reg1b = mode->clock / 5;
163 
164 	buf = udl_set_register_lfsr16(buf, UDL_REG_XDISPLAYSTART, reg01);
165 	buf = udl_set_register_lfsr16(buf, UDL_REG_XDISPLAYEND, reg03);
166 	buf = udl_set_register_lfsr16(buf, UDL_REG_YDISPLAYSTART, reg05);
167 	buf = udl_set_register_lfsr16(buf, UDL_REG_YDISPLAYEND, reg07);
168 	buf = udl_set_register_lfsr16(buf, UDL_REG_XENDCOUNT, reg09);
169 	buf = udl_set_register_lfsr16(buf, UDL_REG_HSYNCSTART, reg0b);
170 	buf = udl_set_register_lfsr16(buf, UDL_REG_HSYNCEND, reg0d);
171 	buf = udl_set_register_16(buf, UDL_REG_HPIXELS, reg0f);
172 	buf = udl_set_register_lfsr16(buf, UDL_REG_YENDCOUNT, reg11);
173 	buf = udl_set_register_lfsr16(buf, UDL_REG_VSYNCSTART, reg13);
174 	buf = udl_set_register_lfsr16(buf, UDL_REG_VSYNCEND, reg15);
175 	buf = udl_set_register_16(buf, UDL_REG_VPIXELS, reg17);
176 	buf = udl_set_register_16be(buf, UDL_REG_PIXELCLOCK5KHZ, reg1b);
177 
178 	return buf;
179 }
180 
181 static char *udl_dummy_render(char *wrptr)
182 {
183 	*wrptr++ = UDL_MSG_BULK;
184 	*wrptr++ = UDL_CMD_WRITECOPY16;
185 	*wrptr++ = 0x00; /* from addr */
186 	*wrptr++ = 0x00;
187 	*wrptr++ = 0x00;
188 	*wrptr++ = 0x01; /* one pixel */
189 	*wrptr++ = 0x00; /* to address */
190 	*wrptr++ = 0x00;
191 	*wrptr++ = 0x00;
192 	return wrptr;
193 }
194 
195 static long udl_log_cpp(unsigned int cpp)
196 {
197 	if (WARN_ON(!is_power_of_2(cpp)))
198 		return -EINVAL;
199 	return __ffs(cpp);
200 }
201 
202 static int udl_handle_damage(struct drm_framebuffer *fb,
203 			     const struct iosys_map *map,
204 			     const struct drm_rect *clip)
205 {
206 	struct drm_device *dev = fb->dev;
207 	void *vaddr = map->vaddr; /* TODO: Use mapping abstraction properly */
208 	int i, ret;
209 	char *cmd;
210 	struct urb *urb;
211 	int log_bpp;
212 
213 	ret = udl_log_cpp(fb->format->cpp[0]);
214 	if (ret < 0)
215 		return ret;
216 	log_bpp = ret;
217 
218 	urb = udl_get_urb(dev);
219 	if (!urb)
220 		return -ENOMEM;
221 	cmd = urb->transfer_buffer;
222 
223 	for (i = clip->y1; i < clip->y2; i++) {
224 		const int line_offset = fb->pitches[0] * i;
225 		const int byte_offset = line_offset + (clip->x1 << log_bpp);
226 		const int dev_byte_offset = (fb->width * i + clip->x1) << log_bpp;
227 		const int byte_width = drm_rect_width(clip) << log_bpp;
228 		ret = udl_render_hline(dev, log_bpp, &urb, (char *)vaddr,
229 				       &cmd, byte_offset, dev_byte_offset,
230 				       byte_width);
231 		if (ret)
232 			return ret;
233 	}
234 
235 	if (cmd > (char *)urb->transfer_buffer) {
236 		/* Send partial buffer remaining before exiting */
237 		int len;
238 		if (cmd < (char *)urb->transfer_buffer + urb->transfer_buffer_length)
239 			*cmd++ = UDL_MSG_BULK;
240 		len = cmd - (char *)urb->transfer_buffer;
241 		ret = udl_submit_urb(dev, urb, len);
242 	} else {
243 		udl_urb_completion(urb);
244 	}
245 
246 	return 0;
247 }
248 
249 /*
250  * Primary plane
251  */
252 
253 static const uint32_t udl_primary_plane_formats[] = {
254 	DRM_FORMAT_RGB565,
255 	DRM_FORMAT_XRGB8888,
256 };
257 
258 static const uint64_t udl_primary_plane_fmtmods[] = {
259 	DRM_FORMAT_MOD_LINEAR,
260 	DRM_FORMAT_MOD_INVALID
261 };
262 
263 static void udl_primary_plane_helper_atomic_update(struct drm_plane *plane,
264 						   struct drm_atomic_state *state)
265 {
266 	struct drm_device *dev = plane->dev;
267 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
268 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
269 	struct drm_framebuffer *fb = plane_state->fb;
270 	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
271 	struct drm_atomic_helper_damage_iter iter;
272 	struct drm_rect damage;
273 	int ret, idx;
274 
275 	if (!fb)
276 		return; /* no framebuffer; plane is disabled */
277 
278 	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
279 	if (ret)
280 		return;
281 
282 	if (!drm_dev_enter(dev, &idx))
283 		goto out_drm_gem_fb_end_cpu_access;
284 
285 	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
286 	drm_atomic_for_each_plane_damage(&iter, &damage) {
287 		udl_handle_damage(fb, &shadow_plane_state->data[0], &damage);
288 	}
289 
290 	drm_dev_exit(idx);
291 
292 out_drm_gem_fb_end_cpu_access:
293 	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
294 }
295 
296 static const struct drm_plane_helper_funcs udl_primary_plane_helper_funcs = {
297 	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
298 	.atomic_check = drm_plane_helper_atomic_check,
299 	.atomic_update = udl_primary_plane_helper_atomic_update,
300 };
301 
302 static const struct drm_plane_funcs udl_primary_plane_funcs = {
303 	.update_plane = drm_atomic_helper_update_plane,
304 	.disable_plane = drm_atomic_helper_disable_plane,
305 	.destroy = drm_plane_cleanup,
306 	DRM_GEM_SHADOW_PLANE_FUNCS,
307 };
308 
309 /*
310  * CRTC
311  */
312 
313 static int udl_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
314 {
315 	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
316 
317 	if (!new_crtc_state->enable)
318 		return 0;
319 
320 	return drm_atomic_helper_check_crtc_primary_plane(new_crtc_state);
321 }
322 
323 static void udl_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state)
324 {
325 	struct drm_device *dev = crtc->dev;
326 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
327 	struct drm_display_mode *mode = &crtc_state->mode;
328 	struct urb *urb;
329 	char *buf;
330 	int idx;
331 
332 	if (!drm_dev_enter(dev, &idx))
333 		return;
334 
335 	urb = udl_get_urb(dev);
336 	if (!urb)
337 		goto out;
338 
339 	buf = (char *)urb->transfer_buffer;
340 	buf = udl_vidreg_lock(buf);
341 	buf = udl_set_color_depth(buf, UDL_COLORDEPTH_16BPP);
342 	/* set base for 16bpp segment to 0 */
343 	buf = udl_set_base16bpp(buf, 0);
344 	/* set base for 8bpp segment to end of fb */
345 	buf = udl_set_base8bpp(buf, 2 * mode->vdisplay * mode->hdisplay);
346 	buf = udl_set_display_mode(buf, mode);
347 	buf = udl_set_blank_mode(buf, UDL_BLANKMODE_ON);
348 	buf = udl_vidreg_unlock(buf);
349 	buf = udl_dummy_render(buf);
350 
351 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
352 
353 out:
354 	drm_dev_exit(idx);
355 }
356 
357 static void udl_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state)
358 {
359 	struct drm_device *dev = crtc->dev;
360 	struct urb *urb;
361 	char *buf;
362 	int idx;
363 
364 	if (!drm_dev_enter(dev, &idx))
365 		return;
366 
367 	urb = udl_get_urb(dev);
368 	if (!urb)
369 		goto out;
370 
371 	buf = (char *)urb->transfer_buffer;
372 	buf = udl_vidreg_lock(buf);
373 	buf = udl_set_blank_mode(buf, UDL_BLANKMODE_POWERDOWN);
374 	buf = udl_vidreg_unlock(buf);
375 	buf = udl_dummy_render(buf);
376 
377 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
378 
379 out:
380 	drm_dev_exit(idx);
381 }
382 
383 static const struct drm_crtc_helper_funcs udl_crtc_helper_funcs = {
384 	.atomic_check = udl_crtc_helper_atomic_check,
385 	.atomic_enable = udl_crtc_helper_atomic_enable,
386 	.atomic_disable = udl_crtc_helper_atomic_disable,
387 };
388 
389 static const struct drm_crtc_funcs udl_crtc_funcs = {
390 	.reset = drm_atomic_helper_crtc_reset,
391 	.destroy = drm_crtc_cleanup,
392 	.set_config = drm_atomic_helper_set_config,
393 	.page_flip = drm_atomic_helper_page_flip,
394 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
395 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
396 };
397 
398 /*
399  * Encoder
400  */
401 
402 static const struct drm_encoder_funcs udl_encoder_funcs = {
403 	.destroy = drm_encoder_cleanup,
404 };
405 
406 /*
407  * Connector
408  */
409 
410 static int udl_connector_helper_get_modes(struct drm_connector *connector)
411 {
412 	struct udl_connector *udl_connector = to_udl_connector(connector);
413 
414 	drm_connector_update_edid_property(connector, udl_connector->edid);
415 	if (udl_connector->edid)
416 		return drm_add_edid_modes(connector, udl_connector->edid);
417 
418 	return 0;
419 }
420 
421 static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
422 	.get_modes = udl_connector_helper_get_modes,
423 };
424 
425 static int udl_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
426 {
427 	struct udl_device *udl = data;
428 	struct drm_device *dev = &udl->drm;
429 	struct usb_device *udev = udl_to_usb_device(udl);
430 	u8 *read_buff;
431 	int ret;
432 	size_t i;
433 
434 	read_buff = kmalloc(2, GFP_KERNEL);
435 	if (!read_buff)
436 		return -ENOMEM;
437 
438 	for (i = 0; i < len; i++) {
439 		int bval = (i + block * EDID_LENGTH) << 8;
440 
441 		ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
442 				      0x02, (0x80 | (0x02 << 5)), bval,
443 				      0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
444 		if (ret < 0) {
445 			drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
446 			goto err_kfree;
447 		} else if (ret < 1) {
448 			ret = -EIO;
449 			drm_err(dev, "Read EDID byte %zu failed\n", i);
450 			goto err_kfree;
451 		}
452 
453 		buf[i] = read_buff[1];
454 	}
455 
456 	kfree(read_buff);
457 
458 	return 0;
459 
460 err_kfree:
461 	kfree(read_buff);
462 	return ret;
463 }
464 
465 static enum drm_connector_status udl_connector_detect(struct drm_connector *connector, bool force)
466 {
467 	struct drm_device *dev = connector->dev;
468 	struct udl_device *udl = to_udl(dev);
469 	struct udl_connector *udl_connector = to_udl_connector(connector);
470 	enum drm_connector_status status = connector_status_disconnected;
471 	int idx;
472 
473 	/* cleanup previous EDID */
474 	kfree(udl_connector->edid);
475 	udl_connector->edid = NULL;
476 
477 	if (!drm_dev_enter(dev, &idx))
478 		return connector_status_disconnected;
479 
480 	udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, udl);
481 	if (udl_connector->edid)
482 		status = connector_status_connected;
483 
484 	drm_dev_exit(idx);
485 
486 	return status;
487 }
488 
489 static void udl_connector_destroy(struct drm_connector *connector)
490 {
491 	struct udl_connector *udl_connector = to_udl_connector(connector);
492 
493 	drm_connector_cleanup(connector);
494 	kfree(udl_connector->edid);
495 	kfree(udl_connector);
496 }
497 
498 static const struct drm_connector_funcs udl_connector_funcs = {
499 	.reset = drm_atomic_helper_connector_reset,
500 	.detect = udl_connector_detect,
501 	.fill_modes = drm_helper_probe_single_connector_modes,
502 	.destroy = udl_connector_destroy,
503 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
504 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
505 };
506 
507 struct drm_connector *udl_connector_init(struct drm_device *dev)
508 {
509 	struct udl_connector *udl_connector;
510 	struct drm_connector *connector;
511 	int ret;
512 
513 	udl_connector = kzalloc(sizeof(*udl_connector), GFP_KERNEL);
514 	if (!udl_connector)
515 		return ERR_PTR(-ENOMEM);
516 
517 	connector = &udl_connector->connector;
518 	ret = drm_connector_init(dev, connector, &udl_connector_funcs, DRM_MODE_CONNECTOR_VGA);
519 	if (ret)
520 		goto err_kfree;
521 
522 	drm_connector_helper_add(connector, &udl_connector_helper_funcs);
523 
524 	connector->polled = DRM_CONNECTOR_POLL_HPD |
525 			    DRM_CONNECTOR_POLL_CONNECT |
526 			    DRM_CONNECTOR_POLL_DISCONNECT;
527 
528 	return connector;
529 
530 err_kfree:
531 	kfree(udl_connector);
532 	return ERR_PTR(ret);
533 }
534 
535 /*
536  * Modesetting
537  */
538 
539 static enum drm_mode_status udl_mode_config_mode_valid(struct drm_device *dev,
540 						       const struct drm_display_mode *mode)
541 {
542 	struct udl_device *udl = to_udl(dev);
543 
544 	if (udl->sku_pixel_limit) {
545 		if (mode->vdisplay * mode->hdisplay > udl->sku_pixel_limit)
546 			return MODE_MEM;
547 	}
548 
549 	return MODE_OK;
550 }
551 
552 static const struct drm_mode_config_funcs udl_mode_config_funcs = {
553 	.fb_create = drm_gem_fb_create_with_dirty,
554 	.mode_valid = udl_mode_config_mode_valid,
555 	.atomic_check  = drm_atomic_helper_check,
556 	.atomic_commit = drm_atomic_helper_commit,
557 };
558 
559 int udl_modeset_init(struct drm_device *dev)
560 {
561 	struct udl_device *udl = to_udl(dev);
562 	struct drm_plane *primary_plane;
563 	struct drm_crtc *crtc;
564 	struct drm_encoder *encoder;
565 	struct drm_connector *connector;
566 	int ret;
567 
568 	ret = drmm_mode_config_init(dev);
569 	if (ret)
570 		return ret;
571 
572 	dev->mode_config.min_width = 640;
573 	dev->mode_config.min_height = 480;
574 	dev->mode_config.max_width = 2048;
575 	dev->mode_config.max_height = 2048;
576 	dev->mode_config.preferred_depth = 16;
577 	dev->mode_config.funcs = &udl_mode_config_funcs;
578 
579 	primary_plane = &udl->primary_plane;
580 	ret = drm_universal_plane_init(dev, primary_plane, 0,
581 				       &udl_primary_plane_funcs,
582 				       udl_primary_plane_formats,
583 				       ARRAY_SIZE(udl_primary_plane_formats),
584 				       udl_primary_plane_fmtmods,
585 				       DRM_PLANE_TYPE_PRIMARY, NULL);
586 	if (ret)
587 		return ret;
588 	drm_plane_helper_add(primary_plane, &udl_primary_plane_helper_funcs);
589 	drm_plane_enable_fb_damage_clips(primary_plane);
590 
591 	crtc = &udl->crtc;
592 	ret = drm_crtc_init_with_planes(dev, crtc, primary_plane, NULL,
593 					&udl_crtc_funcs, NULL);
594 	if (ret)
595 		return ret;
596 	drm_crtc_helper_add(crtc, &udl_crtc_helper_funcs);
597 
598 	encoder = &udl->encoder;
599 	ret = drm_encoder_init(dev, encoder, &udl_encoder_funcs, DRM_MODE_ENCODER_DAC, NULL);
600 	if (ret)
601 		return ret;
602 	encoder->possible_crtcs = drm_crtc_mask(crtc);
603 
604 	connector = udl_connector_init(dev);
605 	if (IS_ERR(connector))
606 		return PTR_ERR(connector);
607 	ret = drm_connector_attach_encoder(connector, encoder);
608 	if (ret)
609 		return ret;
610 
611 	drm_mode_config_reset(dev);
612 
613 	return 0;
614 }
615