xref: /linux/drivers/gpu/drm/gma500/cdv_intel_lvds.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2006-2011 Intel Corporation
4  *
5  * Authors:
6  *	Eric Anholt <eric@anholt.net>
7  *	Dave Airlie <airlied@linux.ie>
8  *	Jesse Barnes <jesse.barnes@intel.com>
9  */
10 
11 #include <linux/dmi.h>
12 #include <linux/i2c.h>
13 #include <linux/pm_runtime.h>
14 
15 #include <drm/drm_crtc_helper.h>
16 #include <drm/drm_modeset_helper_vtables.h>
17 #include <drm/drm_simple_kms_helper.h>
18 
19 #include "cdv_device.h"
20 #include "intel_bios.h"
21 #include "power.h"
22 #include "psb_drv.h"
23 #include "psb_intel_drv.h"
24 #include "psb_intel_reg.h"
25 
26 /*
27  * LVDS I2C backlight control macros
28  */
29 #define BRIGHTNESS_MAX_LEVEL 100
30 #define BRIGHTNESS_MASK 0xFF
31 #define BLC_I2C_TYPE	0x01
32 #define BLC_PWM_TYPT	0x02
33 
34 #define BLC_POLARITY_NORMAL 0
35 #define BLC_POLARITY_INVERSE 1
36 
37 #define PSB_BLC_MAX_PWM_REG_FREQ       (0xFFFE)
38 #define PSB_BLC_MIN_PWM_REG_FREQ	(0x2)
39 #define PSB_BLC_PWM_PRECISION_FACTOR	(10)
40 #define PSB_BACKLIGHT_PWM_CTL_SHIFT	(16)
41 #define PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR (0xFFFE)
42 
43 struct cdv_intel_lvds_priv {
44 	/**
45 	 * Saved LVDO output states
46 	 */
47 	uint32_t savePP_ON;
48 	uint32_t savePP_OFF;
49 	uint32_t saveLVDS;
50 	uint32_t savePP_CONTROL;
51 	uint32_t savePP_CYCLE;
52 	uint32_t savePFIT_CONTROL;
53 	uint32_t savePFIT_PGM_RATIOS;
54 	uint32_t saveBLC_PWM_CTL;
55 };
56 
57 /*
58  * Returns the maximum level of the backlight duty cycle field.
59  */
cdv_intel_lvds_get_max_backlight(struct drm_device * dev)60 static u32 cdv_intel_lvds_get_max_backlight(struct drm_device *dev)
61 {
62 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
63 	u32 retval;
64 
65 	if (gma_power_begin(dev, false)) {
66 		retval = ((REG_READ(BLC_PWM_CTL) &
67 			  BACKLIGHT_MODULATION_FREQ_MASK) >>
68 			  BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
69 
70 		gma_power_end(dev);
71 	} else
72 		retval = ((dev_priv->regs.saveBLC_PWM_CTL &
73 			  BACKLIGHT_MODULATION_FREQ_MASK) >>
74 			  BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
75 
76 	return retval;
77 }
78 
79 /*
80  * Sets the backlight level.
81  *
82  * level backlight level, from 0 to cdv_intel_lvds_get_max_backlight().
83  */
cdv_intel_lvds_set_backlight(struct drm_device * dev,int level)84 static void cdv_intel_lvds_set_backlight(struct drm_device *dev, int level)
85 {
86 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
87 	u32 blc_pwm_ctl;
88 
89 	if (gma_power_begin(dev, false)) {
90 		blc_pwm_ctl =
91 			REG_READ(BLC_PWM_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
92 		REG_WRITE(BLC_PWM_CTL,
93 				(blc_pwm_ctl |
94 				(level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
95 		gma_power_end(dev);
96 	} else {
97 		blc_pwm_ctl = dev_priv->regs.saveBLC_PWM_CTL &
98 				~BACKLIGHT_DUTY_CYCLE_MASK;
99 		dev_priv->regs.saveBLC_PWM_CTL = (blc_pwm_ctl |
100 					(level << BACKLIGHT_DUTY_CYCLE_SHIFT));
101 	}
102 }
103 
104 /*
105  * Sets the power state for the panel.
106  */
cdv_intel_lvds_set_power(struct drm_device * dev,struct drm_encoder * encoder,bool on)107 static void cdv_intel_lvds_set_power(struct drm_device *dev,
108 				     struct drm_encoder *encoder, bool on)
109 {
110 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
111 	u32 pp_status;
112 
113 	if (!gma_power_begin(dev, true))
114 		return;
115 
116 	if (on) {
117 		REG_WRITE(PP_CONTROL, REG_READ(PP_CONTROL) |
118 			  POWER_TARGET_ON);
119 		do {
120 			pp_status = REG_READ(PP_STATUS);
121 		} while ((pp_status & PP_ON) == 0);
122 
123 		cdv_intel_lvds_set_backlight(dev,
124 				dev_priv->mode_dev.backlight_duty_cycle);
125 	} else {
126 		cdv_intel_lvds_set_backlight(dev, 0);
127 
128 		REG_WRITE(PP_CONTROL, REG_READ(PP_CONTROL) &
129 			  ~POWER_TARGET_ON);
130 		do {
131 			pp_status = REG_READ(PP_STATUS);
132 		} while (pp_status & PP_ON);
133 	}
134 	gma_power_end(dev);
135 }
136 
cdv_intel_lvds_encoder_dpms(struct drm_encoder * encoder,int mode)137 static void cdv_intel_lvds_encoder_dpms(struct drm_encoder *encoder, int mode)
138 {
139 	struct drm_device *dev = encoder->dev;
140 	if (mode == DRM_MODE_DPMS_ON)
141 		cdv_intel_lvds_set_power(dev, encoder, true);
142 	else
143 		cdv_intel_lvds_set_power(dev, encoder, false);
144 	/* XXX: We never power down the LVDS pairs. */
145 }
146 
cdv_intel_lvds_save(struct drm_connector * connector)147 static void cdv_intel_lvds_save(struct drm_connector *connector)
148 {
149 }
150 
cdv_intel_lvds_restore(struct drm_connector * connector)151 static void cdv_intel_lvds_restore(struct drm_connector *connector)
152 {
153 }
154 
cdv_intel_lvds_mode_valid(struct drm_connector * connector,struct drm_display_mode * mode)155 static enum drm_mode_status cdv_intel_lvds_mode_valid(struct drm_connector *connector,
156 			      struct drm_display_mode *mode)
157 {
158 	struct drm_device *dev = connector->dev;
159 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
160 	struct drm_display_mode *fixed_mode =
161 					dev_priv->mode_dev.panel_fixed_mode;
162 
163 	/* just in case */
164 	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
165 		return MODE_NO_DBLESCAN;
166 
167 	/* just in case */
168 	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
169 		return MODE_NO_INTERLACE;
170 
171 	if (fixed_mode) {
172 		if (mode->hdisplay > fixed_mode->hdisplay)
173 			return MODE_PANEL;
174 		if (mode->vdisplay > fixed_mode->vdisplay)
175 			return MODE_PANEL;
176 	}
177 	return MODE_OK;
178 }
179 
cdv_intel_lvds_mode_fixup(struct drm_encoder * encoder,const struct drm_display_mode * mode,struct drm_display_mode * adjusted_mode)180 static bool cdv_intel_lvds_mode_fixup(struct drm_encoder *encoder,
181 				  const struct drm_display_mode *mode,
182 				  struct drm_display_mode *adjusted_mode)
183 {
184 	struct drm_device *dev = encoder->dev;
185 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
186 	struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
187 	struct drm_encoder *tmp_encoder;
188 	struct drm_display_mode *panel_fixed_mode = mode_dev->panel_fixed_mode;
189 
190 	/* Should never happen!! */
191 	list_for_each_entry(tmp_encoder, &dev->mode_config.encoder_list,
192 			    head) {
193 		if (tmp_encoder != encoder
194 		    && tmp_encoder->crtc == encoder->crtc) {
195 			pr_err("Can't enable LVDS and another encoder on the same pipe\n");
196 			return false;
197 		}
198 	}
199 
200 	/*
201 	 * If we have timings from the BIOS for the panel, put them in
202 	 * to the adjusted mode.  The CRTC will be set up for this mode,
203 	 * with the panel scaling set up to source from the H/VDisplay
204 	 * of the original mode.
205 	 */
206 	if (panel_fixed_mode != NULL) {
207 		adjusted_mode->hdisplay = panel_fixed_mode->hdisplay;
208 		adjusted_mode->hsync_start = panel_fixed_mode->hsync_start;
209 		adjusted_mode->hsync_end = panel_fixed_mode->hsync_end;
210 		adjusted_mode->htotal = panel_fixed_mode->htotal;
211 		adjusted_mode->vdisplay = panel_fixed_mode->vdisplay;
212 		adjusted_mode->vsync_start = panel_fixed_mode->vsync_start;
213 		adjusted_mode->vsync_end = panel_fixed_mode->vsync_end;
214 		adjusted_mode->vtotal = panel_fixed_mode->vtotal;
215 		adjusted_mode->clock = panel_fixed_mode->clock;
216 		drm_mode_set_crtcinfo(adjusted_mode,
217 				      CRTC_INTERLACE_HALVE_V);
218 	}
219 
220 	/*
221 	 * XXX: It would be nice to support lower refresh rates on the
222 	 * panels to reduce power consumption, and perhaps match the
223 	 * user's requested refresh rate.
224 	 */
225 
226 	return true;
227 }
228 
cdv_intel_lvds_prepare(struct drm_encoder * encoder)229 static void cdv_intel_lvds_prepare(struct drm_encoder *encoder)
230 {
231 	struct drm_device *dev = encoder->dev;
232 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
233 	struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
234 
235 	if (!gma_power_begin(dev, true))
236 		return;
237 
238 	mode_dev->saveBLC_PWM_CTL = REG_READ(BLC_PWM_CTL);
239 	mode_dev->backlight_duty_cycle = (mode_dev->saveBLC_PWM_CTL &
240 					  BACKLIGHT_DUTY_CYCLE_MASK);
241 
242 	cdv_intel_lvds_set_power(dev, encoder, false);
243 
244 	gma_power_end(dev);
245 }
246 
cdv_intel_lvds_commit(struct drm_encoder * encoder)247 static void cdv_intel_lvds_commit(struct drm_encoder *encoder)
248 {
249 	struct drm_device *dev = encoder->dev;
250 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
251 	struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
252 
253 	if (mode_dev->backlight_duty_cycle == 0)
254 		mode_dev->backlight_duty_cycle =
255 		    cdv_intel_lvds_get_max_backlight(dev);
256 
257 	cdv_intel_lvds_set_power(dev, encoder, true);
258 }
259 
cdv_intel_lvds_mode_set(struct drm_encoder * encoder,struct drm_display_mode * mode,struct drm_display_mode * adjusted_mode)260 static void cdv_intel_lvds_mode_set(struct drm_encoder *encoder,
261 				struct drm_display_mode *mode,
262 				struct drm_display_mode *adjusted_mode)
263 {
264 	struct drm_device *dev = encoder->dev;
265 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
266 	struct gma_crtc *gma_crtc = to_gma_crtc(encoder->crtc);
267 	u32 pfit_control;
268 
269 	/*
270 	 * The LVDS pin pair will already have been turned on in the
271 	 * cdv_intel_crtc_mode_set since it has a large impact on the DPLL
272 	 * settings.
273 	 */
274 
275 	/*
276 	 * Enable automatic panel scaling so that non-native modes fill the
277 	 * screen.  Should be enabled before the pipe is enabled, according to
278 	 * register description and PRM.
279 	 */
280 	if (mode->hdisplay != adjusted_mode->hdisplay ||
281 	    mode->vdisplay != adjusted_mode->vdisplay)
282 		pfit_control = (PFIT_ENABLE | VERT_AUTO_SCALE |
283 				HORIZ_AUTO_SCALE | VERT_INTERP_BILINEAR |
284 				HORIZ_INTERP_BILINEAR);
285 	else
286 		pfit_control = 0;
287 
288 	pfit_control |= gma_crtc->pipe << PFIT_PIPE_SHIFT;
289 
290 	if (dev_priv->lvds_dither)
291 		pfit_control |= PANEL_8TO6_DITHER_ENABLE;
292 
293 	REG_WRITE(PFIT_CONTROL, pfit_control);
294 }
295 
296 /*
297  * Return the list of DDC modes if available, or the BIOS fixed mode otherwise.
298  */
cdv_intel_lvds_get_modes(struct drm_connector * connector)299 static int cdv_intel_lvds_get_modes(struct drm_connector *connector)
300 {
301 	struct drm_device *dev = connector->dev;
302 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
303 	struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
304 	int ret;
305 
306 	ret = psb_intel_ddc_get_modes(connector, connector->ddc);
307 
308 	if (ret)
309 		return ret;
310 
311 	if (mode_dev->panel_fixed_mode != NULL) {
312 		struct drm_display_mode *mode =
313 		    drm_mode_duplicate(dev, mode_dev->panel_fixed_mode);
314 		if (!mode)
315 			return 0;
316 
317 		drm_mode_probed_add(connector, mode);
318 		return 1;
319 	}
320 
321 	return 0;
322 }
323 
cdv_intel_lvds_destroy(struct drm_connector * connector)324 static void cdv_intel_lvds_destroy(struct drm_connector *connector)
325 {
326 	struct gma_connector *gma_connector = to_gma_connector(connector);
327 	struct gma_encoder *gma_encoder = gma_attached_encoder(connector);
328 
329 	gma_i2c_destroy(to_gma_i2c_chan(connector->ddc));
330 	gma_i2c_destroy(gma_encoder->i2c_bus);
331 	drm_connector_cleanup(connector);
332 	kfree(gma_connector);
333 }
334 
cdv_intel_lvds_set_property(struct drm_connector * connector,struct drm_property * property,uint64_t value)335 static int cdv_intel_lvds_set_property(struct drm_connector *connector,
336 				       struct drm_property *property,
337 				       uint64_t value)
338 {
339 	struct drm_encoder *encoder = connector->encoder;
340 
341 	if (!strcmp(property->name, "scaling mode") && encoder) {
342 		struct gma_crtc *crtc = to_gma_crtc(encoder->crtc);
343 		uint64_t curValue;
344 
345 		if (!crtc)
346 			return -1;
347 
348 		switch (value) {
349 		case DRM_MODE_SCALE_FULLSCREEN:
350 			break;
351 		case DRM_MODE_SCALE_NO_SCALE:
352 			break;
353 		case DRM_MODE_SCALE_ASPECT:
354 			break;
355 		default:
356 			return -1;
357 		}
358 
359 		if (drm_object_property_get_value(&connector->base,
360 						     property,
361 						     &curValue))
362 			return -1;
363 
364 		if (curValue == value)
365 			return 0;
366 
367 		if (drm_object_property_set_value(&connector->base,
368 							property,
369 							value))
370 			return -1;
371 
372 		if (crtc->saved_mode.hdisplay != 0 &&
373 		    crtc->saved_mode.vdisplay != 0) {
374 			if (!drm_crtc_helper_set_mode(encoder->crtc,
375 						      &crtc->saved_mode,
376 						      encoder->crtc->x,
377 						      encoder->crtc->y,
378 						      encoder->crtc->primary->fb))
379 				return -1;
380 		}
381 	} else if (!strcmp(property->name, "backlight") && encoder) {
382 		if (drm_object_property_set_value(&connector->base,
383 							property,
384 							value))
385 			return -1;
386 		else
387                         gma_backlight_set(encoder->dev, value);
388 	} else if (!strcmp(property->name, "DPMS") && encoder) {
389 		const struct drm_encoder_helper_funcs *helpers =
390 					encoder->helper_private;
391 		helpers->dpms(encoder, value);
392 	}
393 	return 0;
394 }
395 
396 static const struct drm_encoder_helper_funcs
397 					cdv_intel_lvds_helper_funcs = {
398 	.dpms = cdv_intel_lvds_encoder_dpms,
399 	.mode_fixup = cdv_intel_lvds_mode_fixup,
400 	.prepare = cdv_intel_lvds_prepare,
401 	.mode_set = cdv_intel_lvds_mode_set,
402 	.commit = cdv_intel_lvds_commit,
403 };
404 
405 static const struct drm_connector_helper_funcs
406 				cdv_intel_lvds_connector_helper_funcs = {
407 	.get_modes = cdv_intel_lvds_get_modes,
408 	.mode_valid = cdv_intel_lvds_mode_valid,
409 	.best_encoder = gma_best_encoder,
410 };
411 
412 static const struct drm_connector_funcs cdv_intel_lvds_connector_funcs = {
413 	.dpms = drm_helper_connector_dpms,
414 	.fill_modes = drm_helper_probe_single_connector_modes,
415 	.set_property = cdv_intel_lvds_set_property,
416 	.destroy = cdv_intel_lvds_destroy,
417 };
418 
419 /*
420  * Enumerate the child dev array parsed from VBT to check whether
421  * the LVDS is present.
422  * If it is present, return 1.
423  * If it is not present, return false.
424  * If no child dev is parsed from VBT, it assumes that the LVDS is present.
425  */
lvds_is_present_in_vbt(struct drm_device * dev,u8 * i2c_pin)426 static bool lvds_is_present_in_vbt(struct drm_device *dev,
427 				   u8 *i2c_pin)
428 {
429 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
430 	int i;
431 
432 	if (!dev_priv->child_dev_num)
433 		return true;
434 
435 	for (i = 0; i < dev_priv->child_dev_num; i++) {
436 		struct child_device_config *child = dev_priv->child_dev + i;
437 
438 		/* If the device type is not LFP, continue.
439 		 * We have to check both the new identifiers as well as the
440 		 * old for compatibility with some BIOSes.
441 		 */
442 		if (child->device_type != DEVICE_TYPE_INT_LFP &&
443 		    child->device_type != DEVICE_TYPE_LFP)
444 			continue;
445 
446 		if (child->i2c_pin)
447 		    *i2c_pin = child->i2c_pin;
448 
449 		/* However, we cannot trust the BIOS writers to populate
450 		 * the VBT correctly.  Since LVDS requires additional
451 		 * information from AIM blocks, a non-zero addin offset is
452 		 * a good indicator that the LVDS is actually present.
453 		 */
454 		if (child->addin_offset)
455 			return true;
456 
457 		/* But even then some BIOS writers perform some black magic
458 		 * and instantiate the device without reference to any
459 		 * additional data.  Trust that if the VBT was written into
460 		 * the OpRegion then they have validated the LVDS's existence.
461 		 */
462 		if (dev_priv->opregion.vbt)
463 			return true;
464 	}
465 
466 	return false;
467 }
468 
469 /**
470  * cdv_intel_lvds_init - setup LVDS connectors on this device
471  * @dev: drm device
472  * @mode_dev: PSB mode device
473  *
474  * Create the connector, register the LVDS DDC bus, and try to figure out what
475  * modes we can display on the LVDS panel (if present).
476  */
cdv_intel_lvds_init(struct drm_device * dev,struct psb_intel_mode_device * mode_dev)477 void cdv_intel_lvds_init(struct drm_device *dev,
478 		     struct psb_intel_mode_device *mode_dev)
479 {
480 	struct gma_encoder *gma_encoder;
481 	struct gma_connector *gma_connector;
482 	struct cdv_intel_lvds_priv *lvds_priv;
483 	struct drm_connector *connector;
484 	struct drm_encoder *encoder;
485 	struct drm_display_mode *scan;
486 	struct drm_crtc *crtc;
487 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
488 	struct gma_i2c_chan *ddc_bus;
489 	u32 lvds;
490 	int pipe;
491 	int ret;
492 	u8 pin;
493 
494 	if (!dev_priv->lvds_enabled_in_vbt)
495 		return;
496 
497 	pin = GMBUS_PORT_PANEL;
498 	if (!lvds_is_present_in_vbt(dev, &pin)) {
499 		DRM_DEBUG_KMS("LVDS is not present in VBT\n");
500 		return;
501 	}
502 
503 	gma_encoder = kzalloc(sizeof(struct gma_encoder),
504 				    GFP_KERNEL);
505 	if (!gma_encoder)
506 		return;
507 
508 	gma_connector = kzalloc(sizeof(struct gma_connector),
509 				      GFP_KERNEL);
510 	if (!gma_connector)
511 		goto err_free_encoder;
512 
513 	lvds_priv = kzalloc(sizeof(struct cdv_intel_lvds_priv), GFP_KERNEL);
514 	if (!lvds_priv)
515 		goto err_free_connector;
516 
517 	gma_encoder->dev_priv = lvds_priv;
518 
519 	connector = &gma_connector->base;
520 	gma_connector->save = cdv_intel_lvds_save;
521 	gma_connector->restore = cdv_intel_lvds_restore;
522 	encoder = &gma_encoder->base;
523 
524 	/* Set up the DDC bus. */
525 	ddc_bus = gma_i2c_create(dev, GPIOC, "LVDSDDC_C");
526 	if (!ddc_bus) {
527 		dev_printk(KERN_ERR, dev->dev,
528 			   "DDC bus registration " "failed.\n");
529 		goto err_free_lvds_priv;
530 	}
531 
532 	ret = drm_connector_init_with_ddc(dev, connector,
533 					  &cdv_intel_lvds_connector_funcs,
534 					  DRM_MODE_CONNECTOR_LVDS,
535 					  &ddc_bus->base);
536 	if (ret)
537 		goto err_destroy_ddc;
538 
539 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_LVDS);
540 	if (ret)
541 		goto err_connector_cleanup;
542 
543 	gma_connector_attach_encoder(gma_connector, gma_encoder);
544 	gma_encoder->type = INTEL_OUTPUT_LVDS;
545 
546 	drm_encoder_helper_add(encoder, &cdv_intel_lvds_helper_funcs);
547 	drm_connector_helper_add(connector,
548 				 &cdv_intel_lvds_connector_helper_funcs);
549 	connector->display_info.subpixel_order = SubPixelHorizontalRGB;
550 	connector->interlace_allowed = false;
551 	connector->doublescan_allowed = false;
552 
553 	/*Attach connector properties*/
554 	drm_object_attach_property(&connector->base,
555 				      dev->mode_config.scaling_mode_property,
556 				      DRM_MODE_SCALE_FULLSCREEN);
557 	drm_object_attach_property(&connector->base,
558 				      dev_priv->backlight_property,
559 				      BRIGHTNESS_MAX_LEVEL);
560 
561 	/**
562 	 * Set up I2C bus
563 	 * FIXME: distroy i2c_bus when exit
564 	 */
565 	gma_encoder->i2c_bus = gma_i2c_create(dev, GPIOB, "LVDSBLC_B");
566 	if (!gma_encoder->i2c_bus) {
567 		dev_printk(KERN_ERR,
568 			dev->dev, "I2C bus registration failed.\n");
569 		goto err_encoder_cleanup;
570 	}
571 	gma_encoder->i2c_bus->target_addr = 0x2C;
572 	dev_priv->lvds_i2c_bus = gma_encoder->i2c_bus;
573 
574 	/*
575 	 * LVDS discovery:
576 	 * 1) check for EDID on DDC
577 	 * 2) check for VBT data
578 	 * 3) check to see if LVDS is already on
579 	 *    if none of the above, no panel
580 	 * 4) make sure lid is open
581 	 *    if closed, act like it's not there for now
582 	 */
583 
584 	/*
585 	 * Attempt to get the fixed panel mode from DDC.  Assume that the
586 	 * preferred mode is the right one.
587 	 */
588 	mutex_lock(&dev->mode_config.mutex);
589 	psb_intel_ddc_get_modes(connector, &ddc_bus->base);
590 
591 	list_for_each_entry(scan, &connector->probed_modes, head) {
592 		if (scan->type & DRM_MODE_TYPE_PREFERRED) {
593 			mode_dev->panel_fixed_mode =
594 			    drm_mode_duplicate(dev, scan);
595 			goto out;	/* FIXME: check for quirks */
596 		}
597 	}
598 
599 	/* Failed to get EDID, what about VBT? do we need this?*/
600 	if (dev_priv->lfp_lvds_vbt_mode) {
601 		mode_dev->panel_fixed_mode =
602 			drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
603 		if (mode_dev->panel_fixed_mode) {
604 			mode_dev->panel_fixed_mode->type |=
605 				DRM_MODE_TYPE_PREFERRED;
606 			goto out;	/* FIXME: check for quirks */
607 		}
608 	}
609 	/*
610 	 * If we didn't get EDID, try checking if the panel is already turned
611 	 * on.	If so, assume that whatever is currently programmed is the
612 	 * correct mode.
613 	 */
614 	lvds = REG_READ(LVDS);
615 	pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
616 	crtc = psb_intel_get_crtc_from_pipe(dev, pipe);
617 
618 	if (crtc && (lvds & LVDS_PORT_EN)) {
619 		mode_dev->panel_fixed_mode =
620 		    cdv_intel_crtc_mode_get(dev, crtc);
621 		if (mode_dev->panel_fixed_mode) {
622 			mode_dev->panel_fixed_mode->type |=
623 			    DRM_MODE_TYPE_PREFERRED;
624 			goto out;	/* FIXME: check for quirks */
625 		}
626 	}
627 
628 	/* If we still don't have a mode after all that, give up. */
629 	if (!mode_dev->panel_fixed_mode) {
630 		DRM_DEBUG
631 			("Found no modes on the lvds, ignoring the LVDS\n");
632 		goto err_unlock;
633 	}
634 
635 	/* setup PWM */
636 	{
637 		u32 pwm;
638 
639 		pwm = REG_READ(BLC_PWM_CTL2);
640 		if (pipe == 1)
641 			pwm |= PWM_PIPE_B;
642 		else
643 			pwm &= ~PWM_PIPE_B;
644 		pwm |= PWM_ENABLE;
645 		REG_WRITE(BLC_PWM_CTL2, pwm);
646 	}
647 
648 out:
649 	mutex_unlock(&dev->mode_config.mutex);
650 	return;
651 
652 err_unlock:
653 	mutex_unlock(&dev->mode_config.mutex);
654 	gma_i2c_destroy(gma_encoder->i2c_bus);
655 err_encoder_cleanup:
656 	drm_encoder_cleanup(encoder);
657 err_connector_cleanup:
658 	drm_connector_cleanup(connector);
659 err_destroy_ddc:
660 	gma_i2c_destroy(ddc_bus);
661 err_free_lvds_priv:
662 	kfree(lvds_priv);
663 err_free_connector:
664 	kfree(gma_connector);
665 err_free_encoder:
666 	kfree(gma_encoder);
667 }
668