xref: /openbmc/linux/drivers/gpu/drm/udl/udl_modeset.c (revision 3e50b639)
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_crtc_helper.h>
16 #include <drm/drm_damage_helper.h>
17 #include <drm/drm_drv.h>
18 #include <drm/drm_edid.h>
19 #include <drm/drm_fourcc.h>
20 #include <drm/drm_gem_atomic_helper.h>
21 #include <drm/drm_gem_framebuffer_helper.h>
22 #include <drm/drm_gem_shmem_helper.h>
23 #include <drm/drm_modeset_helper_vtables.h>
24 #include <drm/drm_plane_helper.h>
25 #include <drm/drm_probe_helper.h>
26 #include <drm/drm_vblank.h>
27 
28 #include "udl_drv.h"
29 #include "udl_proto.h"
30 
31 /*
32  * All DisplayLink bulk operations start with 0xaf (UDL_MSG_BULK), followed by
33  * a specific command code. All operations are written to a command buffer, which
34  * the driver sends to the device.
35  */
36 static char *udl_set_register(char *buf, u8 reg, u8 val)
37 {
38 	*buf++ = UDL_MSG_BULK;
39 	*buf++ = UDL_CMD_WRITEREG;
40 	*buf++ = reg;
41 	*buf++ = val;
42 
43 	return buf;
44 }
45 
46 static char *udl_vidreg_lock(char *buf)
47 {
48 	return udl_set_register(buf, UDL_REG_VIDREG, UDL_VIDREG_LOCK);
49 }
50 
51 static char *udl_vidreg_unlock(char *buf)
52 {
53 	return udl_set_register(buf, UDL_REG_VIDREG, UDL_VIDREG_UNLOCK);
54 }
55 
56 static char *udl_set_blank_mode(char *buf, u8 mode)
57 {
58 	return udl_set_register(buf, UDL_REG_BLANKMODE, mode);
59 }
60 
61 static char *udl_set_color_depth(char *buf, u8 selection)
62 {
63 	return udl_set_register(buf, UDL_REG_COLORDEPTH, selection);
64 }
65 
66 static char *udl_set_base16bpp(char *buf, u32 base)
67 {
68 	/* the base pointer is 24 bits wide, 0x20 is hi byte. */
69 	u8 reg20 = FIELD_GET(UDL_BASE_ADDR2_MASK, base);
70 	u8 reg21 = FIELD_GET(UDL_BASE_ADDR1_MASK, base);
71 	u8 reg22 = FIELD_GET(UDL_BASE_ADDR0_MASK, base);
72 
73 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR2, reg20);
74 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR1, reg21);
75 	buf = udl_set_register(buf, UDL_REG_BASE16BPP_ADDR0, reg22);
76 
77 	return buf;
78 }
79 
80 /*
81  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
82  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
83  */
84 static char *udl_set_base8bpp(char *buf, u32 base)
85 {
86 	/* the base pointer is 24 bits wide, 0x26 is hi byte. */
87 	u8 reg26 = FIELD_GET(UDL_BASE_ADDR2_MASK, base);
88 	u8 reg27 = FIELD_GET(UDL_BASE_ADDR1_MASK, base);
89 	u8 reg28 = FIELD_GET(UDL_BASE_ADDR0_MASK, base);
90 
91 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR2, reg26);
92 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR1, reg27);
93 	buf = udl_set_register(buf, UDL_REG_BASE8BPP_ADDR0, reg28);
94 
95 	return buf;
96 }
97 
98 static char *udl_set_register_16(char *wrptr, u8 reg, u16 value)
99 {
100 	wrptr = udl_set_register(wrptr, reg, value >> 8);
101 	return udl_set_register(wrptr, reg+1, value);
102 }
103 
104 /*
105  * This is kind of weird because the controller takes some
106  * register values in a different byte order than other registers.
107  */
108 static char *udl_set_register_16be(char *wrptr, u8 reg, u16 value)
109 {
110 	wrptr = udl_set_register(wrptr, reg, value);
111 	return udl_set_register(wrptr, reg+1, value >> 8);
112 }
113 
114 /*
115  * LFSR is linear feedback shift register. The reason we have this is
116  * because the display controller needs to minimize the clock depth of
117  * various counters used in the display path. So this code reverses the
118  * provided value into the lfsr16 value by counting backwards to get
119  * the value that needs to be set in the hardware comparator to get the
120  * same actual count. This makes sense once you read above a couple of
121  * times and think about it from a hardware perspective.
122  */
123 static u16 udl_lfsr16(u16 actual_count)
124 {
125 	u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
126 
127 	while (actual_count--) {
128 		lv =	 ((lv << 1) |
129 			(((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
130 			& 0xFFFF;
131 	}
132 
133 	return (u16) lv;
134 }
135 
136 /*
137  * This does LFSR conversion on the value that is to be written.
138  * See LFSR explanation above for more detail.
139  */
140 static char *udl_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
141 {
142 	return udl_set_register_16(wrptr, reg, udl_lfsr16(value));
143 }
144 
145 /*
146  * Takes a DRM display mode and converts it into the DisplayLink
147  * equivalent register commands.
148  */
149 static char *udl_set_display_mode(char *buf, struct drm_display_mode *mode)
150 {
151 	u16 reg01 = mode->crtc_htotal - mode->crtc_hsync_start;
152 	u16 reg03 = reg01 + mode->crtc_hdisplay;
153 	u16 reg05 = mode->crtc_vtotal - mode->crtc_vsync_start;
154 	u16 reg07 = reg05 + mode->crtc_vdisplay;
155 	u16 reg09 = mode->crtc_htotal - 1;
156 	u16 reg0b = 1; /* libdlo hardcodes hsync start to 1 */
157 	u16 reg0d = mode->crtc_hsync_end - mode->crtc_hsync_start + 1;
158 	u16 reg0f = mode->hdisplay;
159 	u16 reg11 = mode->crtc_vtotal;
160 	u16 reg13 = 0; /* libdlo hardcodes vsync start to 0 */
161 	u16 reg15 = mode->crtc_vsync_end - mode->crtc_vsync_start;
162 	u16 reg17 = mode->crtc_vdisplay;
163 	u16 reg1b = mode->clock / 5;
164 
165 	buf = udl_set_register_lfsr16(buf, UDL_REG_XDISPLAYSTART, reg01);
166 	buf = udl_set_register_lfsr16(buf, UDL_REG_XDISPLAYEND, reg03);
167 	buf = udl_set_register_lfsr16(buf, UDL_REG_YDISPLAYSTART, reg05);
168 	buf = udl_set_register_lfsr16(buf, UDL_REG_YDISPLAYEND, reg07);
169 	buf = udl_set_register_lfsr16(buf, UDL_REG_XENDCOUNT, reg09);
170 	buf = udl_set_register_lfsr16(buf, UDL_REG_HSYNCSTART, reg0b);
171 	buf = udl_set_register_lfsr16(buf, UDL_REG_HSYNCEND, reg0d);
172 	buf = udl_set_register_16(buf, UDL_REG_HPIXELS, reg0f);
173 	buf = udl_set_register_lfsr16(buf, UDL_REG_YENDCOUNT, reg11);
174 	buf = udl_set_register_lfsr16(buf, UDL_REG_VSYNCSTART, reg13);
175 	buf = udl_set_register_lfsr16(buf, UDL_REG_VSYNCEND, reg15);
176 	buf = udl_set_register_16(buf, UDL_REG_VPIXELS, reg17);
177 	buf = udl_set_register_16be(buf, UDL_REG_PIXELCLOCK5KHZ, reg1b);
178 
179 	return buf;
180 }
181 
182 static char *udl_dummy_render(char *wrptr)
183 {
184 	*wrptr++ = UDL_MSG_BULK;
185 	*wrptr++ = UDL_CMD_WRITECOPY16;
186 	*wrptr++ = 0x00; /* from addr */
187 	*wrptr++ = 0x00;
188 	*wrptr++ = 0x00;
189 	*wrptr++ = 0x01; /* one pixel */
190 	*wrptr++ = 0x00; /* to address */
191 	*wrptr++ = 0x00;
192 	*wrptr++ = 0x00;
193 	return wrptr;
194 }
195 
196 static long udl_log_cpp(unsigned int cpp)
197 {
198 	if (WARN_ON(!is_power_of_2(cpp)))
199 		return -EINVAL;
200 	return __ffs(cpp);
201 }
202 
203 static int udl_handle_damage(struct drm_framebuffer *fb,
204 			     const struct iosys_map *map,
205 			     const struct drm_rect *clip)
206 {
207 	struct drm_device *dev = fb->dev;
208 	void *vaddr = map->vaddr; /* TODO: Use mapping abstraction properly */
209 	int i, ret;
210 	char *cmd;
211 	struct urb *urb;
212 	int log_bpp;
213 
214 	ret = udl_log_cpp(fb->format->cpp[0]);
215 	if (ret < 0)
216 		return ret;
217 	log_bpp = ret;
218 
219 	urb = udl_get_urb(dev);
220 	if (!urb)
221 		return -ENOMEM;
222 	cmd = urb->transfer_buffer;
223 
224 	for (i = clip->y1; i < clip->y2; i++) {
225 		const int line_offset = fb->pitches[0] * i;
226 		const int byte_offset = line_offset + (clip->x1 << log_bpp);
227 		const int dev_byte_offset = (fb->width * i + clip->x1) << log_bpp;
228 		const int byte_width = drm_rect_width(clip) << log_bpp;
229 		ret = udl_render_hline(dev, log_bpp, &urb, (char *)vaddr,
230 				       &cmd, byte_offset, dev_byte_offset,
231 				       byte_width);
232 		if (ret)
233 			return ret;
234 	}
235 
236 	if (cmd > (char *)urb->transfer_buffer) {
237 		/* Send partial buffer remaining before exiting */
238 		int len;
239 		if (cmd < (char *)urb->transfer_buffer + urb->transfer_buffer_length)
240 			*cmd++ = UDL_MSG_BULK;
241 		len = cmd - (char *)urb->transfer_buffer;
242 		ret = udl_submit_urb(dev, urb, len);
243 	} else {
244 		udl_urb_completion(urb);
245 	}
246 
247 	return 0;
248 }
249 
250 /*
251  * Primary plane
252  */
253 
254 static const uint32_t udl_primary_plane_formats[] = {
255 	DRM_FORMAT_RGB565,
256 	DRM_FORMAT_XRGB8888,
257 };
258 
259 static const uint64_t udl_primary_plane_fmtmods[] = {
260 	DRM_FORMAT_MOD_LINEAR,
261 	DRM_FORMAT_MOD_INVALID
262 };
263 
264 static void udl_primary_plane_helper_atomic_update(struct drm_plane *plane,
265 						   struct drm_atomic_state *state)
266 {
267 	struct drm_device *dev = plane->dev;
268 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
269 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
270 	struct drm_framebuffer *fb = plane_state->fb;
271 	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
272 	struct drm_atomic_helper_damage_iter iter;
273 	struct drm_rect damage;
274 	int ret, idx;
275 
276 	if (!fb)
277 		return; /* no framebuffer; plane is disabled */
278 
279 	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
280 	if (ret)
281 		return;
282 
283 	if (!drm_dev_enter(dev, &idx))
284 		goto out_drm_gem_fb_end_cpu_access;
285 
286 	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
287 	drm_atomic_for_each_plane_damage(&iter, &damage) {
288 		udl_handle_damage(fb, &shadow_plane_state->data[0], &damage);
289 	}
290 
291 	drm_dev_exit(idx);
292 
293 out_drm_gem_fb_end_cpu_access:
294 	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
295 }
296 
297 static const struct drm_plane_helper_funcs udl_primary_plane_helper_funcs = {
298 	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
299 	.atomic_check = drm_plane_helper_atomic_check,
300 	.atomic_update = udl_primary_plane_helper_atomic_update,
301 };
302 
303 static const struct drm_plane_funcs udl_primary_plane_funcs = {
304 	.update_plane = drm_atomic_helper_update_plane,
305 	.disable_plane = drm_atomic_helper_disable_plane,
306 	.destroy = drm_plane_cleanup,
307 	DRM_GEM_SHADOW_PLANE_FUNCS,
308 };
309 
310 /*
311  * CRTC
312  */
313 
314 static int udl_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
315 {
316 	struct drm_crtc_state *new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
317 
318 	if (!new_crtc_state->enable)
319 		return 0;
320 
321 	return drm_atomic_helper_check_crtc_primary_plane(new_crtc_state);
322 }
323 
324 static void udl_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state)
325 {
326 	struct drm_device *dev = crtc->dev;
327 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
328 	struct drm_display_mode *mode = &crtc_state->mode;
329 	struct urb *urb;
330 	char *buf;
331 	int idx;
332 
333 	if (!drm_dev_enter(dev, &idx))
334 		return;
335 
336 	urb = udl_get_urb(dev);
337 	if (!urb)
338 		goto out;
339 
340 	buf = (char *)urb->transfer_buffer;
341 	buf = udl_vidreg_lock(buf);
342 	buf = udl_set_color_depth(buf, UDL_COLORDEPTH_16BPP);
343 	/* set base for 16bpp segment to 0 */
344 	buf = udl_set_base16bpp(buf, 0);
345 	/* set base for 8bpp segment to end of fb */
346 	buf = udl_set_base8bpp(buf, 2 * mode->vdisplay * mode->hdisplay);
347 	buf = udl_set_display_mode(buf, mode);
348 	buf = udl_set_blank_mode(buf, UDL_BLANKMODE_ON);
349 	buf = udl_vidreg_unlock(buf);
350 	buf = udl_dummy_render(buf);
351 
352 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
353 
354 out:
355 	drm_dev_exit(idx);
356 }
357 
358 static void udl_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state)
359 {
360 	struct drm_device *dev = crtc->dev;
361 	struct urb *urb;
362 	char *buf;
363 	int idx;
364 
365 	if (!drm_dev_enter(dev, &idx))
366 		return;
367 
368 	urb = udl_get_urb(dev);
369 	if (!urb)
370 		goto out;
371 
372 	buf = (char *)urb->transfer_buffer;
373 	buf = udl_vidreg_lock(buf);
374 	buf = udl_set_blank_mode(buf, UDL_BLANKMODE_POWERDOWN);
375 	buf = udl_vidreg_unlock(buf);
376 	buf = udl_dummy_render(buf);
377 
378 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
379 
380 out:
381 	drm_dev_exit(idx);
382 }
383 
384 static const struct drm_crtc_helper_funcs udl_crtc_helper_funcs = {
385 	.atomic_check = udl_crtc_helper_atomic_check,
386 	.atomic_enable = udl_crtc_helper_atomic_enable,
387 	.atomic_disable = udl_crtc_helper_atomic_disable,
388 };
389 
390 static const struct drm_crtc_funcs udl_crtc_funcs = {
391 	.reset = drm_atomic_helper_crtc_reset,
392 	.destroy = drm_crtc_cleanup,
393 	.set_config = drm_atomic_helper_set_config,
394 	.page_flip = drm_atomic_helper_page_flip,
395 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
396 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
397 };
398 
399 /*
400  * Encoder
401  */
402 
403 static const struct drm_encoder_funcs udl_encoder_funcs = {
404 	.destroy = drm_encoder_cleanup,
405 };
406 
407 /*
408  * Connector
409  */
410 
411 static int udl_connector_helper_get_modes(struct drm_connector *connector)
412 {
413 	struct udl_connector *udl_connector = to_udl_connector(connector);
414 
415 	drm_connector_update_edid_property(connector, udl_connector->edid);
416 	if (udl_connector->edid)
417 		return drm_add_edid_modes(connector, udl_connector->edid);
418 
419 	return 0;
420 }
421 
422 static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
423 	.get_modes = udl_connector_helper_get_modes,
424 };
425 
426 static int udl_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
427 {
428 	struct udl_device *udl = data;
429 	struct drm_device *dev = &udl->drm;
430 	struct usb_device *udev = udl_to_usb_device(udl);
431 	u8 *read_buff;
432 	int ret;
433 	size_t i;
434 
435 	read_buff = kmalloc(2, GFP_KERNEL);
436 	if (!read_buff)
437 		return -ENOMEM;
438 
439 	for (i = 0; i < len; i++) {
440 		int bval = (i + block * EDID_LENGTH) << 8;
441 
442 		ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
443 				      0x02, (0x80 | (0x02 << 5)), bval,
444 				      0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
445 		if (ret < 0) {
446 			drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
447 			goto err_kfree;
448 		} else if (ret < 1) {
449 			ret = -EIO;
450 			drm_err(dev, "Read EDID byte %zu failed\n", i);
451 			goto err_kfree;
452 		}
453 
454 		buf[i] = read_buff[1];
455 	}
456 
457 	kfree(read_buff);
458 
459 	return 0;
460 
461 err_kfree:
462 	kfree(read_buff);
463 	return ret;
464 }
465 
466 static enum drm_connector_status udl_connector_detect(struct drm_connector *connector, bool force)
467 {
468 	struct drm_device *dev = connector->dev;
469 	struct udl_device *udl = to_udl(dev);
470 	struct udl_connector *udl_connector = to_udl_connector(connector);
471 	enum drm_connector_status status = connector_status_disconnected;
472 	int idx;
473 
474 	/* cleanup previous EDID */
475 	kfree(udl_connector->edid);
476 	udl_connector->edid = NULL;
477 
478 	if (!drm_dev_enter(dev, &idx))
479 		return connector_status_disconnected;
480 
481 	udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, udl);
482 	if (udl_connector->edid)
483 		status = connector_status_connected;
484 
485 	drm_dev_exit(idx);
486 
487 	return status;
488 }
489 
490 static void udl_connector_destroy(struct drm_connector *connector)
491 {
492 	struct udl_connector *udl_connector = to_udl_connector(connector);
493 
494 	drm_connector_cleanup(connector);
495 	kfree(udl_connector->edid);
496 	kfree(udl_connector);
497 }
498 
499 static const struct drm_connector_funcs udl_connector_funcs = {
500 	.reset = drm_atomic_helper_connector_reset,
501 	.detect = udl_connector_detect,
502 	.fill_modes = drm_helper_probe_single_connector_modes,
503 	.destroy = udl_connector_destroy,
504 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
505 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
506 };
507 
508 struct drm_connector *udl_connector_init(struct drm_device *dev)
509 {
510 	struct udl_connector *udl_connector;
511 	struct drm_connector *connector;
512 	int ret;
513 
514 	udl_connector = kzalloc(sizeof(*udl_connector), GFP_KERNEL);
515 	if (!udl_connector)
516 		return ERR_PTR(-ENOMEM);
517 
518 	connector = &udl_connector->connector;
519 	ret = drm_connector_init(dev, connector, &udl_connector_funcs, DRM_MODE_CONNECTOR_VGA);
520 	if (ret)
521 		goto err_kfree;
522 
523 	drm_connector_helper_add(connector, &udl_connector_helper_funcs);
524 
525 	connector->polled = DRM_CONNECTOR_POLL_HPD |
526 			    DRM_CONNECTOR_POLL_CONNECT |
527 			    DRM_CONNECTOR_POLL_DISCONNECT;
528 
529 	return connector;
530 
531 err_kfree:
532 	kfree(udl_connector);
533 	return ERR_PTR(ret);
534 }
535 
536 /*
537  * Modesetting
538  */
539 
540 static enum drm_mode_status udl_mode_config_mode_valid(struct drm_device *dev,
541 						       const struct drm_display_mode *mode)
542 {
543 	struct udl_device *udl = to_udl(dev);
544 
545 	if (udl->sku_pixel_limit) {
546 		if (mode->vdisplay * mode->hdisplay > udl->sku_pixel_limit)
547 			return MODE_MEM;
548 	}
549 
550 	return MODE_OK;
551 }
552 
553 static const struct drm_mode_config_funcs udl_mode_config_funcs = {
554 	.fb_create = drm_gem_fb_create_with_dirty,
555 	.mode_valid = udl_mode_config_mode_valid,
556 	.atomic_check  = drm_atomic_helper_check,
557 	.atomic_commit = drm_atomic_helper_commit,
558 };
559 
560 int udl_modeset_init(struct drm_device *dev)
561 {
562 	struct udl_device *udl = to_udl(dev);
563 	struct drm_plane *primary_plane;
564 	struct drm_crtc *crtc;
565 	struct drm_encoder *encoder;
566 	struct drm_connector *connector;
567 	int ret;
568 
569 	ret = drmm_mode_config_init(dev);
570 	if (ret)
571 		return ret;
572 
573 	dev->mode_config.min_width = 640;
574 	dev->mode_config.min_height = 480;
575 	dev->mode_config.max_width = 2048;
576 	dev->mode_config.max_height = 2048;
577 	dev->mode_config.preferred_depth = 16;
578 	dev->mode_config.funcs = &udl_mode_config_funcs;
579 
580 	primary_plane = &udl->primary_plane;
581 	ret = drm_universal_plane_init(dev, primary_plane, 0,
582 				       &udl_primary_plane_funcs,
583 				       udl_primary_plane_formats,
584 				       ARRAY_SIZE(udl_primary_plane_formats),
585 				       udl_primary_plane_fmtmods,
586 				       DRM_PLANE_TYPE_PRIMARY, NULL);
587 	if (ret)
588 		return ret;
589 	drm_plane_helper_add(primary_plane, &udl_primary_plane_helper_funcs);
590 	drm_plane_enable_fb_damage_clips(primary_plane);
591 
592 	crtc = &udl->crtc;
593 	ret = drm_crtc_init_with_planes(dev, crtc, primary_plane, NULL,
594 					&udl_crtc_funcs, NULL);
595 	if (ret)
596 		return ret;
597 	drm_crtc_helper_add(crtc, &udl_crtc_helper_funcs);
598 
599 	encoder = &udl->encoder;
600 	ret = drm_encoder_init(dev, encoder, &udl_encoder_funcs, DRM_MODE_ENCODER_DAC, NULL);
601 	if (ret)
602 		return ret;
603 	encoder->possible_crtcs = drm_crtc_mask(crtc);
604 
605 	connector = udl_connector_init(dev);
606 	if (IS_ERR(connector))
607 		return PTR_ERR(connector);
608 	ret = drm_connector_attach_encoder(connector, encoder);
609 	if (ret)
610 		return ret;
611 
612 	drm_mode_config_reset(dev);
613 
614 	return 0;
615 }
616