treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / gpu / drm / gma500 / cdv_intel_lvds.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright © 2006-2011 Intel Corporation
 *
 * Authors:
 *      Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */

#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/pm_runtime.h>

#include "cdv_device.h"
#include "intel_bios.h"
#include "power.h"
#include "psb_drv.h"
#include "psb_intel_drv.h"
#include "psb_intel_reg.h"

/**
 * LVDS I2C backlight control macros
 */
#define BRIGHTNESS_MAX_LEVEL 100
#define BRIGHTNESS_MASK 0xFF
#define BLC_I2C_TYPE    0x01
#define BLC_PWM_TYPT    0x02

#define BLC_POLARITY_NORMAL 0
#define BLC_POLARITY_INVERSE 1

#define PSB_BLC_MAX_PWM_REG_FREQ       (0xFFFE)
#define PSB_BLC_MIN_PWM_REG_FREQ        (0x2)
#define PSB_BLC_PWM_PRECISION_FACTOR    (10)
#define PSB_BACKLIGHT_PWM_CTL_SHIFT     (16)
#define PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR (0xFFFE)

struct cdv_intel_lvds_priv {
        /**
         * Saved LVDO output states
         */
        uint32_t savePP_ON;
        uint32_t savePP_OFF;
        uint32_t saveLVDS;
        uint32_t savePP_CONTROL;
        uint32_t savePP_CYCLE;
        uint32_t savePFIT_CONTROL;
        uint32_t savePFIT_PGM_RATIOS;
        uint32_t saveBLC_PWM_CTL;
};

/*
 * Returns the maximum level of the backlight duty cycle field.
 */
static u32 cdv_intel_lvds_get_max_backlight(struct drm_device *dev)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 retval;

        if (gma_power_begin(dev, false)) {
                retval = ((REG_READ(BLC_PWM_CTL) &
                          BACKLIGHT_MODULATION_FREQ_MASK) >>
                          BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;

                gma_power_end(dev);
        } else
                retval = ((dev_priv->regs.saveBLC_PWM_CTL &
                          BACKLIGHT_MODULATION_FREQ_MASK) >>
                          BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;

        return retval;
}

#if 0
/*
 * Set LVDS backlight level by I2C command
 */
static int cdv_lvds_i2c_set_brightness(struct drm_device *dev,
                                        unsigned int level)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct psb_intel_i2c_chan *lvds_i2c_bus = dev_priv->lvds_i2c_bus;
        u8 out_buf[2];
        unsigned int blc_i2c_brightness;

        struct i2c_msg msgs[] = {
                {
                        .addr = lvds_i2c_bus->slave_addr,
                        .flags = 0,
                        .len = 2,
                        .buf = out_buf,
                }
        };

        blc_i2c_brightness = BRIGHTNESS_MASK & ((unsigned int)level *
                             BRIGHTNESS_MASK /
                             BRIGHTNESS_MAX_LEVEL);

        if (dev_priv->lvds_bl->pol == BLC_POLARITY_INVERSE)
                blc_i2c_brightness = BRIGHTNESS_MASK - blc_i2c_brightness;

        out_buf[0] = dev_priv->lvds_bl->brightnesscmd;
        out_buf[1] = (u8)blc_i2c_brightness;

        if (i2c_transfer(&lvds_i2c_bus->adapter, msgs, 1) == 1)
                return 0;

        DRM_ERROR("I2C transfer error\n");
        return -1;
}


static int cdv_lvds_pwm_set_brightness(struct drm_device *dev, int level)
{
        struct drm_psb_private *dev_priv = dev->dev_private;

        u32 max_pwm_blc;
        u32 blc_pwm_duty_cycle;

        max_pwm_blc = cdv_intel_lvds_get_max_backlight(dev);

        /*BLC_PWM_CTL Should be initiated while backlight device init*/
        BUG_ON((max_pwm_blc & PSB_BLC_MAX_PWM_REG_FREQ) == 0);

        blc_pwm_duty_cycle = level * max_pwm_blc / BRIGHTNESS_MAX_LEVEL;

        if (dev_priv->lvds_bl->pol == BLC_POLARITY_INVERSE)
                blc_pwm_duty_cycle = max_pwm_blc - blc_pwm_duty_cycle;

        blc_pwm_duty_cycle &= PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR;
        REG_WRITE(BLC_PWM_CTL,
                  (max_pwm_blc << PSB_BACKLIGHT_PWM_CTL_SHIFT) |
                  (blc_pwm_duty_cycle));

        return 0;
}

/*
 * Set LVDS backlight level either by I2C or PWM
 */
void cdv_intel_lvds_set_brightness(struct drm_device *dev, int level)
{
        struct drm_psb_private *dev_priv = dev->dev_private;

        if (!dev_priv->lvds_bl) {
                DRM_ERROR("NO LVDS Backlight Info\n");
                return;
        }

        if (dev_priv->lvds_bl->type == BLC_I2C_TYPE)
                cdv_lvds_i2c_set_brightness(dev, level);
        else
                cdv_lvds_pwm_set_brightness(dev, level);
}
#endif

/**
 * Sets the backlight level.
 *
 * level backlight level, from 0 to cdv_intel_lvds_get_max_backlight().
 */
static void cdv_intel_lvds_set_backlight(struct drm_device *dev, int level)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 blc_pwm_ctl;

        if (gma_power_begin(dev, false)) {
                blc_pwm_ctl =
                        REG_READ(BLC_PWM_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
                REG_WRITE(BLC_PWM_CTL,
                                (blc_pwm_ctl |
                                (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
                gma_power_end(dev);
        } else {
                blc_pwm_ctl = dev_priv->regs.saveBLC_PWM_CTL &
                                ~BACKLIGHT_DUTY_CYCLE_MASK;
                dev_priv->regs.saveBLC_PWM_CTL = (blc_pwm_ctl |
                                        (level << BACKLIGHT_DUTY_CYCLE_SHIFT));
        }
}

/**
 * Sets the power state for the panel.
 */
static void cdv_intel_lvds_set_power(struct drm_device *dev,
                                     struct drm_encoder *encoder, bool on)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 pp_status;

        if (!gma_power_begin(dev, true))
                return;

        if (on) {
                REG_WRITE(PP_CONTROL, REG_READ(PP_CONTROL) |
                          POWER_TARGET_ON);
                do {
                        pp_status = REG_READ(PP_STATUS);
                } while ((pp_status & PP_ON) == 0);

                cdv_intel_lvds_set_backlight(dev,
                                dev_priv->mode_dev.backlight_duty_cycle);
        } else {
                cdv_intel_lvds_set_backlight(dev, 0);

                REG_WRITE(PP_CONTROL, REG_READ(PP_CONTROL) &
                          ~POWER_TARGET_ON);
                do {
                        pp_status = REG_READ(PP_STATUS);
                } while (pp_status & PP_ON);
        }
        gma_power_end(dev);
}

static void cdv_intel_lvds_encoder_dpms(struct drm_encoder *encoder, int mode)
{
        struct drm_device *dev = encoder->dev;
        if (mode == DRM_MODE_DPMS_ON)
                cdv_intel_lvds_set_power(dev, encoder, true);
        else
                cdv_intel_lvds_set_power(dev, encoder, false);
        /* XXX: We never power down the LVDS pairs. */
}

static void cdv_intel_lvds_save(struct drm_connector *connector)
{
}

static void cdv_intel_lvds_restore(struct drm_connector *connector)
{
}

static enum drm_mode_status cdv_intel_lvds_mode_valid(struct drm_connector *connector,
                              struct drm_display_mode *mode)
{
        struct drm_device *dev = connector->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct drm_display_mode *fixed_mode =
                                        dev_priv->mode_dev.panel_fixed_mode;

        /* just in case */
        if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
                return MODE_NO_DBLESCAN;

        /* just in case */
        if (mode->flags & DRM_MODE_FLAG_INTERLACE)
                return MODE_NO_INTERLACE;

        if (fixed_mode) {
                if (mode->hdisplay > fixed_mode->hdisplay)
                        return MODE_PANEL;
                if (mode->vdisplay > fixed_mode->vdisplay)
                        return MODE_PANEL;
        }
        return MODE_OK;
}

static bool cdv_intel_lvds_mode_fixup(struct drm_encoder *encoder,
                                  const struct drm_display_mode *mode,
                                  struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = encoder->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
        struct drm_encoder *tmp_encoder;
        struct drm_display_mode *panel_fixed_mode = mode_dev->panel_fixed_mode;

        /* Should never happen!! */
        list_for_each_entry(tmp_encoder, &dev->mode_config.encoder_list,
                            head) {
                if (tmp_encoder != encoder
                    && tmp_encoder->crtc == encoder->crtc) {
                        pr_err("Can't enable LVDS and another encoder on the same pipe\n");
                        return false;
                }
        }

        /*
         * If we have timings from the BIOS for the panel, put them in
         * to the adjusted mode.  The CRTC will be set up for this mode,
         * with the panel scaling set up to source from the H/VDisplay
         * of the original mode.
         */
        if (panel_fixed_mode != NULL) {
                adjusted_mode->hdisplay = panel_fixed_mode->hdisplay;
                adjusted_mode->hsync_start = panel_fixed_mode->hsync_start;
                adjusted_mode->hsync_end = panel_fixed_mode->hsync_end;
                adjusted_mode->htotal = panel_fixed_mode->htotal;
                adjusted_mode->vdisplay = panel_fixed_mode->vdisplay;
                adjusted_mode->vsync_start = panel_fixed_mode->vsync_start;
                adjusted_mode->vsync_end = panel_fixed_mode->vsync_end;
                adjusted_mode->vtotal = panel_fixed_mode->vtotal;
                adjusted_mode->clock = panel_fixed_mode->clock;
                drm_mode_set_crtcinfo(adjusted_mode,
                                      CRTC_INTERLACE_HALVE_V);
        }

        /*
         * XXX: It would be nice to support lower refresh rates on the
         * panels to reduce power consumption, and perhaps match the
         * user's requested refresh rate.
         */

        return true;
}

static void cdv_intel_lvds_prepare(struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;

        if (!gma_power_begin(dev, true))
                return;

        mode_dev->saveBLC_PWM_CTL = REG_READ(BLC_PWM_CTL);
        mode_dev->backlight_duty_cycle = (mode_dev->saveBLC_PWM_CTL &
                                          BACKLIGHT_DUTY_CYCLE_MASK);

        cdv_intel_lvds_set_power(dev, encoder, false);

        gma_power_end(dev);
}

static void cdv_intel_lvds_commit(struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;

        if (mode_dev->backlight_duty_cycle == 0)
                mode_dev->backlight_duty_cycle =
                    cdv_intel_lvds_get_max_backlight(dev);

        cdv_intel_lvds_set_power(dev, encoder, true);
}

static void cdv_intel_lvds_mode_set(struct drm_encoder *encoder,
                                struct drm_display_mode *mode,
                                struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = encoder->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct gma_crtc *gma_crtc = to_gma_crtc(encoder->crtc);
        u32 pfit_control;

        /*
         * The LVDS pin pair will already have been turned on in the
         * cdv_intel_crtc_mode_set since it has a large impact on the DPLL
         * settings.
         */

        /*
         * Enable automatic panel scaling so that non-native modes fill the
         * screen.  Should be enabled before the pipe is enabled, according to
         * register description and PRM.
         */
        if (mode->hdisplay != adjusted_mode->hdisplay ||
            mode->vdisplay != adjusted_mode->vdisplay)
                pfit_control = (PFIT_ENABLE | VERT_AUTO_SCALE |
                                HORIZ_AUTO_SCALE | VERT_INTERP_BILINEAR |
                                HORIZ_INTERP_BILINEAR);
        else
                pfit_control = 0;

        pfit_control |= gma_crtc->pipe << PFIT_PIPE_SHIFT;

        if (dev_priv->lvds_dither)
                pfit_control |= PANEL_8TO6_DITHER_ENABLE;

        REG_WRITE(PFIT_CONTROL, pfit_control);
}

/**
 * Return the list of DDC modes if available, or the BIOS fixed mode otherwise.
 */
static int cdv_intel_lvds_get_modes(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        struct gma_encoder *gma_encoder = gma_attached_encoder(connector);
        struct psb_intel_mode_device *mode_dev = &dev_priv->mode_dev;
        int ret;

        ret = psb_intel_ddc_get_modes(connector, &gma_encoder->i2c_bus->adapter);

        if (ret)
                return ret;

        if (mode_dev->panel_fixed_mode != NULL) {
                struct drm_display_mode *mode =
                    drm_mode_duplicate(dev, mode_dev->panel_fixed_mode);
                drm_mode_probed_add(connector, mode);
                return 1;
        }

        return 0;
}

/**
 * cdv_intel_lvds_destroy - unregister and free LVDS structures
 * @connector: connector to free
 *
 * Unregister the DDC bus for this connector then free the driver private
 * structure.
 */
static void cdv_intel_lvds_destroy(struct drm_connector *connector)
{
        struct gma_encoder *gma_encoder = gma_attached_encoder(connector);

        psb_intel_i2c_destroy(gma_encoder->i2c_bus);
        drm_connector_unregister(connector);
        drm_connector_cleanup(connector);
        kfree(connector);
}

static int cdv_intel_lvds_set_property(struct drm_connector *connector,
                                       struct drm_property *property,
                                       uint64_t value)
{
        struct drm_encoder *encoder = connector->encoder;

        if (!strcmp(property->name, "scaling mode") && encoder) {
                struct gma_crtc *crtc = to_gma_crtc(encoder->crtc);
                uint64_t curValue;

                if (!crtc)
                        return -1;

                switch (value) {
                case DRM_MODE_SCALE_FULLSCREEN:
                        break;
                case DRM_MODE_SCALE_NO_SCALE:
                        break;
                case DRM_MODE_SCALE_ASPECT:
                        break;
                default:
                        return -1;
                }

                if (drm_object_property_get_value(&connector->base,
                                                     property,
                                                     &curValue))
                        return -1;

                if (curValue == value)
                        return 0;

                if (drm_object_property_set_value(&connector->base,
                                                        property,
                                                        value))
                        return -1;

                if (crtc->saved_mode.hdisplay != 0 &&
                    crtc->saved_mode.vdisplay != 0) {
                        if (!drm_crtc_helper_set_mode(encoder->crtc,
                                                      &crtc->saved_mode,
                                                      encoder->crtc->x,
                                                      encoder->crtc->y,
                                                      encoder->crtc->primary->fb))
                                return -1;
                }
        } else if (!strcmp(property->name, "backlight") && encoder) {
                if (drm_object_property_set_value(&connector->base,
                                                        property,
                                                        value))
                        return -1;
                else
                        gma_backlight_set(encoder->dev, value);
        } else if (!strcmp(property->name, "DPMS") && encoder) {
                const struct drm_encoder_helper_funcs *helpers =
                                        encoder->helper_private;
                helpers->dpms(encoder, value);
        }
        return 0;
}

static const struct drm_encoder_helper_funcs
                                        cdv_intel_lvds_helper_funcs = {
        .dpms = cdv_intel_lvds_encoder_dpms,
        .mode_fixup = cdv_intel_lvds_mode_fixup,
        .prepare = cdv_intel_lvds_prepare,
        .mode_set = cdv_intel_lvds_mode_set,
        .commit = cdv_intel_lvds_commit,
};

static const struct drm_connector_helper_funcs
                                cdv_intel_lvds_connector_helper_funcs = {
        .get_modes = cdv_intel_lvds_get_modes,
        .mode_valid = cdv_intel_lvds_mode_valid,
        .best_encoder = gma_best_encoder,
};

static const struct drm_connector_funcs cdv_intel_lvds_connector_funcs = {
        .dpms = drm_helper_connector_dpms,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .set_property = cdv_intel_lvds_set_property,
        .destroy = cdv_intel_lvds_destroy,
};


static void cdv_intel_lvds_enc_destroy(struct drm_encoder *encoder)
{
        drm_encoder_cleanup(encoder);
}

static const struct drm_encoder_funcs cdv_intel_lvds_enc_funcs = {
        .destroy = cdv_intel_lvds_enc_destroy,
};

/*
 * Enumerate the child dev array parsed from VBT to check whether
 * the LVDS is present.
 * If it is present, return 1.
 * If it is not present, return false.
 * If no child dev is parsed from VBT, it assumes that the LVDS is present.
 */
static bool lvds_is_present_in_vbt(struct drm_device *dev,
                                   u8 *i2c_pin)
{
        struct drm_psb_private *dev_priv = dev->dev_private;
        int i;

        if (!dev_priv->child_dev_num)
                return true;

        for (i = 0; i < dev_priv->child_dev_num; i++) {
                struct child_device_config *child = dev_priv->child_dev + i;

                /* If the device type is not LFP, continue.
                 * We have to check both the new identifiers as well as the
                 * old for compatibility with some BIOSes.
                 */
                if (child->device_type != DEVICE_TYPE_INT_LFP &&
                    child->device_type != DEVICE_TYPE_LFP)
                        continue;

                if (child->i2c_pin)
                    *i2c_pin = child->i2c_pin;

                /* However, we cannot trust the BIOS writers to populate
                 * the VBT correctly.  Since LVDS requires additional
                 * information from AIM blocks, a non-zero addin offset is
                 * a good indicator that the LVDS is actually present.
                 */
                if (child->addin_offset)
                        return true;

                /* But even then some BIOS writers perform some black magic
                 * and instantiate the device without reference to any
                 * additional data.  Trust that if the VBT was written into
                 * the OpRegion then they have validated the LVDS's existence.
                 */
                if (dev_priv->opregion.vbt)
                        return true;
        }

        return false;
}

/**
 * cdv_intel_lvds_init - setup LVDS connectors on this device
 * @dev: drm device
 *
 * Create the connector, register the LVDS DDC bus, and try to figure out what
 * modes we can display on the LVDS panel (if present).
 */
void cdv_intel_lvds_init(struct drm_device *dev,
                     struct psb_intel_mode_device *mode_dev)
{
        struct gma_encoder *gma_encoder;
        struct gma_connector *gma_connector;
        struct cdv_intel_lvds_priv *lvds_priv;
        struct drm_connector *connector;
        struct drm_encoder *encoder;
        struct drm_display_mode *scan;
        struct drm_crtc *crtc;
        struct drm_psb_private *dev_priv = dev->dev_private;
        u32 lvds;
        int pipe;
        u8 pin;

        if (!dev_priv->lvds_enabled_in_vbt)
                return;

        pin = GMBUS_PORT_PANEL;
        if (!lvds_is_present_in_vbt(dev, &pin)) {
                DRM_DEBUG_KMS("LVDS is not present in VBT\n");
                return;
        }

        gma_encoder = kzalloc(sizeof(struct gma_encoder),
                                    GFP_KERNEL);
        if (!gma_encoder)
                return;

        gma_connector = kzalloc(sizeof(struct gma_connector),
                                      GFP_KERNEL);
        if (!gma_connector)
                goto failed_connector;

        lvds_priv = kzalloc(sizeof(struct cdv_intel_lvds_priv), GFP_KERNEL);
        if (!lvds_priv)
                goto failed_lvds_priv;

        gma_encoder->dev_priv = lvds_priv;

        connector = &gma_connector->base;
        gma_connector->save = cdv_intel_lvds_save;
        gma_connector->restore = cdv_intel_lvds_restore;
        encoder = &gma_encoder->base;


        drm_connector_init(dev, connector,
                           &cdv_intel_lvds_connector_funcs,
                           DRM_MODE_CONNECTOR_LVDS);

        drm_encoder_init(dev, encoder,
                         &cdv_intel_lvds_enc_funcs,
                         DRM_MODE_ENCODER_LVDS, NULL);


        gma_connector_attach_encoder(gma_connector, gma_encoder);
        gma_encoder->type = INTEL_OUTPUT_LVDS;

        drm_encoder_helper_add(encoder, &cdv_intel_lvds_helper_funcs);
        drm_connector_helper_add(connector,
                                 &cdv_intel_lvds_connector_helper_funcs);
        connector->display_info.subpixel_order = SubPixelHorizontalRGB;
        connector->interlace_allowed = false;
        connector->doublescan_allowed = false;

        /*Attach connector properties*/
        drm_object_attach_property(&connector->base,
                                      dev->mode_config.scaling_mode_property,
                                      DRM_MODE_SCALE_FULLSCREEN);
        drm_object_attach_property(&connector->base,
                                      dev_priv->backlight_property,
                                      BRIGHTNESS_MAX_LEVEL);

        /**
         * Set up I2C bus
         * FIXME: distroy i2c_bus when exit
         */
        gma_encoder->i2c_bus = psb_intel_i2c_create(dev,
                                                         GPIOB,
                                                         "LVDSBLC_B");
        if (!gma_encoder->i2c_bus) {
                dev_printk(KERN_ERR,
                        &dev->pdev->dev, "I2C bus registration failed.\n");
                goto failed_blc_i2c;
        }
        gma_encoder->i2c_bus->slave_addr = 0x2C;
        dev_priv->lvds_i2c_bus = gma_encoder->i2c_bus;

        /*
         * LVDS discovery:
         * 1) check for EDID on DDC
         * 2) check for VBT data
         * 3) check to see if LVDS is already on
         *    if none of the above, no panel
         * 4) make sure lid is open
         *    if closed, act like it's not there for now
         */

        /* Set up the DDC bus. */
        gma_encoder->ddc_bus = psb_intel_i2c_create(dev,
                                                         GPIOC,
                                                         "LVDSDDC_C");
        if (!gma_encoder->ddc_bus) {
                dev_printk(KERN_ERR, &dev->pdev->dev,
                           "DDC bus registration " "failed.\n");
                goto failed_ddc;
        }

        /*
         * Attempt to get the fixed panel mode from DDC.  Assume that the
         * preferred mode is the right one.
         */
        mutex_lock(&dev->mode_config.mutex);
        psb_intel_ddc_get_modes(connector,
                                &gma_encoder->ddc_bus->adapter);
        list_for_each_entry(scan, &connector->probed_modes, head) {
                if (scan->type & DRM_MODE_TYPE_PREFERRED) {
                        mode_dev->panel_fixed_mode =
                            drm_mode_duplicate(dev, scan);
                        goto out;       /* FIXME: check for quirks */
                }
        }

        /* Failed to get EDID, what about VBT? do we need this?*/
        if (dev_priv->lfp_lvds_vbt_mode) {
                mode_dev->panel_fixed_mode =
                        drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
                if (mode_dev->panel_fixed_mode) {
                        mode_dev->panel_fixed_mode->type |=
                                DRM_MODE_TYPE_PREFERRED;
                        goto out;       /* FIXME: check for quirks */
                }
        }
        /*
         * If we didn't get EDID, try checking if the panel is already turned
         * on.  If so, assume that whatever is currently programmed is the
         * correct mode.
         */
        lvds = REG_READ(LVDS);
        pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
        crtc = psb_intel_get_crtc_from_pipe(dev, pipe);

        if (crtc && (lvds & LVDS_PORT_EN)) {
                mode_dev->panel_fixed_mode =
                    cdv_intel_crtc_mode_get(dev, crtc);
                if (mode_dev->panel_fixed_mode) {
                        mode_dev->panel_fixed_mode->type |=
                            DRM_MODE_TYPE_PREFERRED;
                        goto out;       /* FIXME: check for quirks */
                }
        }

        /* If we still don't have a mode after all that, give up. */
        if (!mode_dev->panel_fixed_mode) {
                DRM_DEBUG
                        ("Found no modes on the lvds, ignoring the LVDS\n");
                goto failed_find;
        }

        /* setup PWM */
        {
                u32 pwm;

                pwm = REG_READ(BLC_PWM_CTL2);
                if (pipe == 1)
                        pwm |= PWM_PIPE_B;
                else
                        pwm &= ~PWM_PIPE_B;
                pwm |= PWM_ENABLE;
                REG_WRITE(BLC_PWM_CTL2, pwm);
        }

out:
        mutex_unlock(&dev->mode_config.mutex);
        drm_connector_register(connector);
        return;

failed_find:
        mutex_unlock(&dev->mode_config.mutex);
        pr_err("Failed find\n");
        psb_intel_i2c_destroy(gma_encoder->ddc_bus);
failed_ddc:
        pr_err("Failed DDC\n");
        psb_intel_i2c_destroy(gma_encoder->i2c_bus);
failed_blc_i2c:
        pr_err("Failed BLC\n");
        drm_encoder_cleanup(encoder);
        drm_connector_cleanup(connector);
        kfree(lvds_priv);
failed_lvds_priv:
        kfree(gma_connector);
failed_connector:
        kfree(gma_encoder);
}