intel_lvds.c

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/*
 * Copyright © 2006-2007 Intel Corporation
 * Copyright (c) 2006 Dave Airlie <[email protected]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *  Eric Anholt <[email protected]>
 *      Dave Airlie <[email protected]>
 *      Jesse Barnes <[email protected]>
 */

#include <acpi/button.h>
#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include "intel_drv.h"
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include <linux/acpi.h>

/* Private structure for the integrated LVDS support */
struct intel_lvds {
    struct intel_encoder base;

    struct edid *edid;

    int fitting_mode;
    u32 pfit_control;
    u32 pfit_pgm_ratios;
    bool pfit_dirty;

    struct drm_display_mode *fixed_mode;
};

static struct intel_lvds *to_intel_lvds(struct drm_encoder *encoder)
{
    return container_of(encoder, struct intel_lvds, base.base);
}

static struct intel_lvds *intel_attached_lvds(struct drm_connector *connector)
{
    return container_of(intel_attached_encoder(connector),
                struct intel_lvds, base);
}

static bool intel_lvds_get_hw_state(struct intel_encoder *encoder,
                    enum pipe *pipe)
{
    struct drm_device *dev = encoder->base.dev;
    struct drm_i915_private *dev_priv = dev->dev_private;
    u32 lvds_reg, tmp;

    if (HAS_PCH_SPLIT(dev)) {
        lvds_reg = PCH_LVDS;
    } else {
        lvds_reg = LVDS;
    }

    tmp = I915_READ(lvds_reg);

    if (!(tmp & LVDS_PORT_EN))
        return false;

    if (HAS_PCH_CPT(dev))
        *pipe = PORT_TO_PIPE_CPT(tmp);
    else
        *pipe = PORT_TO_PIPE(tmp);

    return true;
}

static void intel_enable_lvds(struct intel_encoder *encoder)
{
    struct drm_device *dev = encoder->base.dev;
    struct intel_lvds *intel_lvds = to_intel_lvds(&encoder->base);
    struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
    struct drm_i915_private *dev_priv = dev->dev_private;
    u32 ctl_reg, lvds_reg, stat_reg;

    if (HAS_PCH_SPLIT(dev)) {
        ctl_reg = PCH_PP_CONTROL;
        lvds_reg = PCH_LVDS;
        stat_reg = PCH_PP_STATUS;
    } else {
        ctl_reg = PP_CONTROL;
        lvds_reg = LVDS;
        stat_reg = PP_STATUS;
    }

    I915_WRITE(lvds_reg, I915_READ(lvds_reg) | LVDS_PORT_EN);

    if (intel_lvds->pfit_dirty) {
        /*
         * Enable automatic panel scaling so that non-native modes
         * fill the screen.  The panel fitter should only be
         * adjusted whilst the pipe is disabled, according to
         * register description and PRM.
         */
        DRM_DEBUG_KMS("applying panel-fitter: %x, %x\n",
                  intel_lvds->pfit_control,
                  intel_lvds->pfit_pgm_ratios);

        I915_WRITE(PFIT_PGM_RATIOS, intel_lvds->pfit_pgm_ratios);
        I915_WRITE(PFIT_CONTROL, intel_lvds->pfit_control);
        intel_lvds->pfit_dirty = false;
    }

    I915_WRITE(ctl_reg, I915_READ(ctl_reg) | POWER_TARGET_ON);
    POSTING_READ(lvds_reg);
    if (wait_for((I915_READ(stat_reg) & PP_ON) != 0, 1000))
        DRM_ERROR("timed out waiting for panel to power on\n");

    intel_panel_enable_backlight(dev, intel_crtc->pipe);
}

static void intel_disable_lvds(struct intel_encoder *encoder)
{
    struct drm_device *dev = encoder->base.dev;
    struct intel_lvds *intel_lvds = to_intel_lvds(&encoder->base);
    struct drm_i915_private *dev_priv = dev->dev_private;
    u32 ctl_reg, lvds_reg, stat_reg;

    if (HAS_PCH_SPLIT(dev)) {
        ctl_reg = PCH_PP_CONTROL;
        lvds_reg = PCH_LVDS;
        stat_reg = PCH_PP_STATUS;
    } else {
        ctl_reg = PP_CONTROL;
        lvds_reg = LVDS;
        stat_reg = PP_STATUS;
    }

    intel_panel_disable_backlight(dev);

    I915_WRITE(ctl_reg, I915_READ(ctl_reg) & ~POWER_TARGET_ON);
    if (wait_for((I915_READ(stat_reg) & PP_ON) == 0, 1000))
        DRM_ERROR("timed out waiting for panel to power off\n");

    if (intel_lvds->pfit_control) {
        I915_WRITE(PFIT_CONTROL, 0);
        intel_lvds->pfit_dirty = true;
    }

    I915_WRITE(lvds_reg, I915_READ(lvds_reg) & ~LVDS_PORT_EN);
    POSTING_READ(lvds_reg);
}

static int intel_lvds_mode_valid(struct drm_connector *connector,
                 struct drm_display_mode *mode)
{
    struct intel_lvds *intel_lvds = intel_attached_lvds(connector);
    struct drm_display_mode *fixed_mode = intel_lvds->fixed_mode;

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

    return MODE_OK;
}

static void
centre_horizontally(struct drm_display_mode *mode,
            int width)
{
    u32 border, sync_pos, blank_width, sync_width;

    /* keep the hsync and hblank widths constant */
    sync_width = mode->crtc_hsync_end - mode->crtc_hsync_start;
    blank_width = mode->crtc_hblank_end - mode->crtc_hblank_start;
    sync_pos = (blank_width - sync_width + 1) / 2;

    border = (mode->hdisplay - width + 1) / 2;
    border += border & 1; /* make the border even */

    mode->crtc_hdisplay = width;
    mode->crtc_hblank_start = width + border;
    mode->crtc_hblank_end = mode->crtc_hblank_start + blank_width;

    mode->crtc_hsync_start = mode->crtc_hblank_start + sync_pos;
    mode->crtc_hsync_end = mode->crtc_hsync_start + sync_width;

    mode->private_flags |= INTEL_MODE_CRTC_TIMINGS_SET;
}

static void
centre_vertically(struct drm_display_mode *mode,
          int height)
{
    u32 border, sync_pos, blank_width, sync_width;

    /* keep the vsync and vblank widths constant */
    sync_width = mode->crtc_vsync_end - mode->crtc_vsync_start;
    blank_width = mode->crtc_vblank_end - mode->crtc_vblank_start;
    sync_pos = (blank_width - sync_width + 1) / 2;

    border = (mode->vdisplay - height + 1) / 2;

    mode->crtc_vdisplay = height;
    mode->crtc_vblank_start = height + border;
    mode->crtc_vblank_end = mode->crtc_vblank_start + blank_width;

    mode->crtc_vsync_start = mode->crtc_vblank_start + sync_pos;
    mode->crtc_vsync_end = mode->crtc_vsync_start + sync_width;

    mode->private_flags |= INTEL_MODE_CRTC_TIMINGS_SET;
}

static inline u32 panel_fitter_scaling(u32 source, u32 target)
{
    /*
     * Floating point operation is not supported. So the FACTOR
     * is defined, which can avoid the floating point computation
     * when calculating the panel ratio.
     */
#define ACCURACY 12
#define FACTOR (1 << ACCURACY)
    u32 ratio = source * FACTOR / target;
    return (FACTOR * ratio + FACTOR/2) / FACTOR;
}

static bool 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_i915_private *dev_priv = dev->dev_private;
    struct intel_lvds *intel_lvds = to_intel_lvds(encoder);
    struct intel_crtc *intel_crtc = intel_lvds->base.new_crtc;
    u32 pfit_control = 0, pfit_pgm_ratios = 0, border = 0;
    int pipe;

    /* Should never happen!! */
    if (INTEL_INFO(dev)->gen < 4 && intel_crtc->pipe == 0) {
        DRM_ERROR("Can't support LVDS on pipe A\n");
        return false;
    }

    if (intel_encoder_check_is_cloned(&intel_lvds->base))
        return false;

    /*
     * 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.
     */
    intel_fixed_panel_mode(intel_lvds->fixed_mode, adjusted_mode);

    if (HAS_PCH_SPLIT(dev)) {
        intel_pch_panel_fitting(dev, intel_lvds->fitting_mode,
                    mode, adjusted_mode);
        return true;
    }

    /* Native modes don't need fitting */
    if (adjusted_mode->hdisplay == mode->hdisplay &&
        adjusted_mode->vdisplay == mode->vdisplay)
        goto out;

    /* 965+ wants fuzzy fitting */
    if (INTEL_INFO(dev)->gen >= 4)
        pfit_control |= ((intel_crtc->pipe << PFIT_PIPE_SHIFT) |
                 PFIT_FILTER_FUZZY);

    /*
     * Enable automatic panel scaling for non-native modes so that they fill
     * the screen.  Should be enabled before the pipe is enabled, according
     * to register description and PRM.
     * Change the value here to see the borders for debugging
     */
    for_each_pipe(pipe)
        I915_WRITE(BCLRPAT(pipe), 0);

    drm_mode_set_crtcinfo(adjusted_mode, 0);

    switch (intel_lvds->fitting_mode) {
    case DRM_MODE_SCALE_CENTER:
        /*
         * For centered modes, we have to calculate border widths &
         * heights and modify the values programmed into the CRTC.
         */
        centre_horizontally(adjusted_mode, mode->hdisplay);
        centre_vertically(adjusted_mode, mode->vdisplay);
        border = LVDS_BORDER_ENABLE;
        break;

    case DRM_MODE_SCALE_ASPECT:
        /* Scale but preserve the aspect ratio */
        if (INTEL_INFO(dev)->gen >= 4) {
            u32 scaled_width = adjusted_mode->hdisplay * mode->vdisplay;
            u32 scaled_height = mode->hdisplay * adjusted_mode->vdisplay;

            /* 965+ is easy, it does everything in hw */
            if (scaled_width > scaled_height)
                pfit_control |= PFIT_ENABLE | PFIT_SCALING_PILLAR;
            else if (scaled_width < scaled_height)
                pfit_control |= PFIT_ENABLE | PFIT_SCALING_LETTER;
            else if (adjusted_mode->hdisplay != mode->hdisplay)
                pfit_control |= PFIT_ENABLE | PFIT_SCALING_AUTO;
        } else {
            u32 scaled_width = adjusted_mode->hdisplay * mode->vdisplay;
            u32 scaled_height = mode->hdisplay * adjusted_mode->vdisplay;
            /*
             * For earlier chips we have to calculate the scaling
             * ratio by hand and program it into the
             * PFIT_PGM_RATIO register
             */
            if (scaled_width > scaled_height) { /* pillar */
                centre_horizontally(adjusted_mode, scaled_height / mode->vdisplay);

                border = LVDS_BORDER_ENABLE;
                if (mode->vdisplay != adjusted_mode->vdisplay) {
                    u32 bits = panel_fitter_scaling(mode->vdisplay, adjusted_mode->vdisplay);
                    pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
                                bits << PFIT_VERT_SCALE_SHIFT);
                    pfit_control |= (PFIT_ENABLE |
                             VERT_INTERP_BILINEAR |
                             HORIZ_INTERP_BILINEAR);
                }
            } else if (scaled_width < scaled_height) { /* letter */
                centre_vertically(adjusted_mode, scaled_width / mode->hdisplay);

                border = LVDS_BORDER_ENABLE;
                if (mode->hdisplay != adjusted_mode->hdisplay) {
                    u32 bits = panel_fitter_scaling(mode->hdisplay, adjusted_mode->hdisplay);
                    pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
                                bits << PFIT_VERT_SCALE_SHIFT);
                    pfit_control |= (PFIT_ENABLE |
                             VERT_INTERP_BILINEAR |
                             HORIZ_INTERP_BILINEAR);
                }
            } else
                /* Aspects match, Let hw scale both directions */
                pfit_control |= (PFIT_ENABLE |
                         VERT_AUTO_SCALE | HORIZ_AUTO_SCALE |
                         VERT_INTERP_BILINEAR |
                         HORIZ_INTERP_BILINEAR);
        }
        break;

    case DRM_MODE_SCALE_FULLSCREEN:
        /*
         * Full scaling, even if it changes the aspect ratio.
         * Fortunately this is all done for us in hw.
         */
        if (mode->vdisplay != adjusted_mode->vdisplay ||
            mode->hdisplay != adjusted_mode->hdisplay) {
            pfit_control |= PFIT_ENABLE;
            if (INTEL_INFO(dev)->gen >= 4)
                pfit_control |= PFIT_SCALING_AUTO;
            else
                pfit_control |= (VERT_AUTO_SCALE |
                         VERT_INTERP_BILINEAR |
                         HORIZ_AUTO_SCALE |
                         HORIZ_INTERP_BILINEAR);
        }
        break;

    default:
        break;
    }

out:
    /* If not enabling scaling, be consistent and always use 0. */
    if ((pfit_control & PFIT_ENABLE) == 0) {
        pfit_control = 0;
        pfit_pgm_ratios = 0;
    }

    /* Make sure pre-965 set dither correctly */
    if (INTEL_INFO(dev)->gen < 4 && dev_priv->lvds_dither)
        pfit_control |= PANEL_8TO6_DITHER_ENABLE;

    if (pfit_control != intel_lvds->pfit_control ||
        pfit_pgm_ratios != intel_lvds->pfit_pgm_ratios) {
        intel_lvds->pfit_control = pfit_control;
        intel_lvds->pfit_pgm_ratios = pfit_pgm_ratios;
        intel_lvds->pfit_dirty = true;
    }
    dev_priv->lvds_border_bits = border;

    /*
     * 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 intel_lvds_mode_set(struct drm_encoder *encoder,
                struct drm_display_mode *mode,
                struct drm_display_mode *adjusted_mode)
{
    /*
     * The LVDS pin pair will already have been turned on in the
     * intel_crtc_mode_set since it has a large impact on the DPLL
     * settings.
     */
}

static enum drm_connector_status
intel_lvds_detect(struct drm_connector *connector, bool force)
{
    struct drm_device *dev = connector->dev;
    enum drm_connector_status status;

    status = intel_panel_detect(dev);
    if (status != connector_status_unknown)
        return status;

    return connector_status_connected;
}

static int intel_lvds_get_modes(struct drm_connector *connector)
{
    struct intel_lvds *intel_lvds = intel_attached_lvds(connector);
    struct drm_device *dev = connector->dev;
    struct drm_display_mode *mode;

    if (intel_lvds->edid)
        return drm_add_edid_modes(connector, intel_lvds->edid);

    mode = drm_mode_duplicate(dev, intel_lvds->fixed_mode);
    if (mode == NULL)
        return 0;

    drm_mode_probed_add(connector, mode);
    return 1;
}

static int intel_no_modeset_on_lid_dmi_callback(const struct dmi_system_id *id)
{
    DRM_INFO("Skipping forced modeset for %s\n", id->ident);
    return 1;
}

/* The GPU hangs up on these systems if modeset is performed on LID open */
static const struct dmi_system_id intel_no_modeset_on_lid[] = {
    {
        .callback = intel_no_modeset_on_lid_dmi_callback,
        .ident = "Toshiba Tecra A11",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
            DMI_MATCH(DMI_PRODUCT_NAME, "TECRA A11"),
        },
    },

    { } /* terminating entry */
};

/*
 * Lid events. Note the use of 'modeset_on_lid':
 *  - we set it on lid close, and reset it on open
 *  - we use it as a "only once" bit (ie we ignore
 *    duplicate events where it was already properly
 *    set/reset)
 *  - the suspend/resume paths will also set it to
 *    zero, since they restore the mode ("lid open").
 */
static int intel_lid_notify(struct notifier_block *nb, unsigned long val,
                void *unused)
{
    struct drm_i915_private *dev_priv =
        container_of(nb, struct drm_i915_private, lid_notifier);
    struct drm_device *dev = dev_priv->dev;
    struct drm_connector *connector = dev_priv->int_lvds_connector;

    if (dev->switch_power_state != DRM_SWITCH_POWER_ON)
        return NOTIFY_OK;

    /*
     * check and update the status of LVDS connector after receiving
     * the LID nofication event.
     */
    if (connector)
        connector->status = connector->funcs->detect(connector,
                                 false);

    /* Don't force modeset on machines where it causes a GPU lockup */
    if (dmi_check_system(intel_no_modeset_on_lid))
        return NOTIFY_OK;
    if (!acpi_lid_open()) {
        dev_priv->modeset_on_lid = 1;
        return NOTIFY_OK;
    }

    if (!dev_priv->modeset_on_lid)
        return NOTIFY_OK;

    dev_priv->modeset_on_lid = 0;

    mutex_lock(&dev->mode_config.mutex);
    intel_modeset_check_state(dev);
    mutex_unlock(&dev->mode_config.mutex);

    return NOTIFY_OK;
}

static void intel_lvds_destroy(struct drm_connector *connector)
{
    struct drm_device *dev = connector->dev;
    struct drm_i915_private *dev_priv = dev->dev_private;

    intel_panel_destroy_backlight(dev);

    if (dev_priv->lid_notifier.notifier_call)
        acpi_lid_notifier_unregister(&dev_priv->lid_notifier);
    drm_sysfs_connector_remove(connector);
    drm_connector_cleanup(connector);
    kfree(connector);
}

static int intel_lvds_set_property(struct drm_connector *connector,
                   struct drm_property *property,
                   uint64_t value)
{
    struct intel_lvds *intel_lvds = intel_attached_lvds(connector);
    struct drm_device *dev = connector->dev;

    if (property == dev->mode_config.scaling_mode_property) {
        struct drm_crtc *crtc = intel_lvds->base.base.crtc;

        if (value == DRM_MODE_SCALE_NONE) {
            DRM_DEBUG_KMS("no scaling not supported\n");
            return -EINVAL;
        }

        if (intel_lvds->fitting_mode == value) {
            /* the LVDS scaling property is not changed */
            return 0;
        }
        intel_lvds->fitting_mode = value;
        if (crtc && crtc->enabled) {
            /*
             * If the CRTC is enabled, the display will be changed
             * according to the new panel fitting mode.
             */
            intel_set_mode(crtc, &crtc->mode,
                       crtc->x, crtc->y, crtc->fb);
        }
    }

    return 0;
}

static const struct drm_encoder_helper_funcs intel_lvds_helper_funcs = {
    .mode_fixup = intel_lvds_mode_fixup,
    .mode_set = intel_lvds_mode_set,
    .disable = intel_encoder_noop,
};

static const struct drm_connector_helper_funcs intel_lvds_connector_helper_funcs = {
    .get_modes = intel_lvds_get_modes,
    .mode_valid = intel_lvds_mode_valid,
    .best_encoder = intel_best_encoder,
};

static const struct drm_connector_funcs intel_lvds_connector_funcs = {
    .dpms = intel_connector_dpms,
    .detect = intel_lvds_detect,
    .fill_modes = drm_helper_probe_single_connector_modes,
    .set_property = intel_lvds_set_property,
    .destroy = intel_lvds_destroy,
};

static const struct drm_encoder_funcs intel_lvds_enc_funcs = {
    .destroy = intel_encoder_destroy,
};

static int __init intel_no_lvds_dmi_callback(const struct dmi_system_id *id)
{
    DRM_INFO("Skipping LVDS initialization for %s\n", id->ident);
    return 1;
}

/* These systems claim to have LVDS, but really don't */
static const struct dmi_system_id intel_no_lvds[] = {
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Apple Mac Mini (Core series)",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
            DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Apple Mac Mini (Core 2 series)",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
            DMI_MATCH(DMI_PRODUCT_NAME, "Macmini2,1"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "MSI IM-945GSE-A",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
            DMI_MATCH(DMI_PRODUCT_NAME, "A9830IMS"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Dell Studio Hybrid",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
            DMI_MATCH(DMI_PRODUCT_NAME, "Studio Hybrid 140g"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Dell OptiPlex FX170",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
            DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex FX170"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "AOpen Mini PC",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "AOpen"),
            DMI_MATCH(DMI_PRODUCT_NAME, "i965GMx-IF"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "AOpen Mini PC MP915",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
            DMI_MATCH(DMI_BOARD_NAME, "i915GMx-F"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "AOpen i915GMm-HFS",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
            DMI_MATCH(DMI_BOARD_NAME, "i915GMm-HFS"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen i45GMx-I",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_BOARD_NAME, "i45GMx-I"),
                },
        },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Aopen i945GTt-VFA",
        .matches = {
            DMI_MATCH(DMI_PRODUCT_VERSION, "AO00001JW"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Clientron U800",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Clientron"),
            DMI_MATCH(DMI_PRODUCT_NAME, "U800"),
        },
    },
    {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Clientron E830",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Clientron"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "E830"),
                },
        },
        {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Asus EeeBox PC EB1007",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer INC."),
            DMI_MATCH(DMI_PRODUCT_NAME, "EB1007"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Asus AT5NM10T-I",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
            DMI_MATCH(DMI_BOARD_NAME, "AT5NM10T-I"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Hewlett-Packard HP t5740e Thin Client",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
            DMI_MATCH(DMI_PRODUCT_NAME, "HP t5740e Thin Client"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Hewlett-Packard t5745",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
            DMI_MATCH(DMI_PRODUCT_NAME, "hp t5745"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Hewlett-Packard st5747",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
            DMI_MATCH(DMI_PRODUCT_NAME, "hp st5747"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "MSI Wind Box DC500",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "MICRO-STAR INTERNATIONAL CO., LTD"),
            DMI_MATCH(DMI_BOARD_NAME, "MS-7469"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "ZOTAC ZBOXSD-ID12/ID13",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "ZOTAC"),
            DMI_MATCH(DMI_BOARD_NAME, "ZBOXSD-ID12/ID13"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Gigabyte GA-D525TUD",
        .matches = {
            DMI_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
            DMI_MATCH(DMI_BOARD_NAME, "D525TUD"),
        },
    },
    {
        .callback = intel_no_lvds_dmi_callback,
        .ident = "Supermicro X7SPA-H",
        .matches = {
            DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
            DMI_MATCH(DMI_PRODUCT_NAME, "X7SPA-H"),
        },
    },

    { } /* terminating entry */
};

static void intel_find_lvds_downclock(struct drm_device *dev,
                      struct drm_display_mode *fixed_mode,
                      struct drm_connector *connector)
{
    struct drm_i915_private *dev_priv = dev->dev_private;
    struct drm_display_mode *scan;
    int temp_downclock;

    temp_downclock = fixed_mode->clock;
    list_for_each_entry(scan, &connector->probed_modes, head) {
        /*
         * If one mode has the same resolution with the fixed_panel
         * mode while they have the different refresh rate, it means
         * that the reduced downclock is found for the LVDS. In such
         * case we can set the different FPx0/1 to dynamically select
         * between low and high frequency.
         */
        if (scan->hdisplay == fixed_mode->hdisplay &&
            scan->hsync_start == fixed_mode->hsync_start &&
            scan->hsync_end == fixed_mode->hsync_end &&
            scan->htotal == fixed_mode->htotal &&
            scan->vdisplay == fixed_mode->vdisplay &&
            scan->vsync_start == fixed_mode->vsync_start &&
            scan->vsync_end == fixed_mode->vsync_end &&
            scan->vtotal == fixed_mode->vtotal) {
            if (scan->clock < temp_downclock) {
                /*
                 * The downclock is already found. But we
                 * expect to find the lower downclock.
                 */
                temp_downclock = scan->clock;
            }
        }
    }
    if (temp_downclock < fixed_mode->clock && i915_lvds_downclock) {
        /* We found the downclock for LVDS. */
        dev_priv->lvds_downclock_avail = 1;
        dev_priv->lvds_downclock = temp_downclock;
        DRM_DEBUG_KMS("LVDS downclock is found in EDID. "
                  "Normal clock %dKhz, downclock %dKhz\n",
                  fixed_mode->clock, temp_downclock);
    }
}

/*
 * 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_i915_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 (intel_gmbus_is_port_valid(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;
}

static bool intel_lvds_supported(struct drm_device *dev)
{
    /* With the introduction of the PCH we gained a dedicated
     * LVDS presence pin, use it. */
    if (HAS_PCH_SPLIT(dev))
        return true;

    /* Otherwise LVDS was only attached to mobile products,
     * except for the inglorious 830gm */
    return IS_MOBILE(dev) && !IS_I830(dev);
}

bool intel_lvds_init(struct drm_device *dev)
{
    struct drm_i915_private *dev_priv = dev->dev_private;
    struct intel_lvds *intel_lvds;
    struct intel_encoder *intel_encoder;
    struct intel_connector *intel_connector;
    struct drm_connector *connector;
    struct drm_encoder *encoder;
    struct drm_display_mode *scan; /* *modes, *bios_mode; */
    struct drm_crtc *crtc;
    u32 lvds;
    int pipe;
    u8 pin;

    if (!intel_lvds_supported(dev))
        return false;

    /* Skip init on machines we know falsely report LVDS */
    if (dmi_check_system(intel_no_lvds))
        return false;

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

    if (HAS_PCH_SPLIT(dev)) {
        if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
            return false;
        if (dev_priv->edp.support) {
            DRM_DEBUG_KMS("disable LVDS for eDP support\n");
            return false;
        }
    }

    intel_lvds = kzalloc(sizeof(struct intel_lvds), GFP_KERNEL);
    if (!intel_lvds) {
        return false;
    }

    intel_connector = kzalloc(sizeof(struct intel_connector), GFP_KERNEL);
    if (!intel_connector) {
        kfree(intel_lvds);
        return false;
    }

    if (!HAS_PCH_SPLIT(dev)) {
        intel_lvds->pfit_control = I915_READ(PFIT_CONTROL);
    }

    intel_encoder = &intel_lvds->base;
    encoder = &intel_encoder->base;
    connector = &intel_connector->base;
    drm_connector_init(dev, &intel_connector->base, &intel_lvds_connector_funcs,
               DRM_MODE_CONNECTOR_LVDS);

    drm_encoder_init(dev, &intel_encoder->base, &intel_lvds_enc_funcs,
             DRM_MODE_ENCODER_LVDS);

    intel_encoder->enable = intel_enable_lvds;
    intel_encoder->disable = intel_disable_lvds;
    intel_encoder->get_hw_state = intel_lvds_get_hw_state;
    intel_connector->get_hw_state = intel_connector_get_hw_state;

    intel_connector_attach_encoder(intel_connector, intel_encoder);
    intel_encoder->type = INTEL_OUTPUT_LVDS;

    intel_encoder->cloneable = false;
    if (HAS_PCH_SPLIT(dev))
        intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
    else if (IS_GEN4(dev))
        intel_encoder->crtc_mask = (1 << 0) | (1 << 1);
    else
        intel_encoder->crtc_mask = (1 << 1);

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

    /* create the scaling mode property */
    drm_mode_create_scaling_mode_property(dev);
    /*
     * the initial panel fitting mode will be FULL_SCREEN.
     */

    drm_connector_attach_property(&intel_connector->base,
                      dev->mode_config.scaling_mode_property,
                      DRM_MODE_SCALE_ASPECT);
    intel_lvds->fitting_mode = DRM_MODE_SCALE_ASPECT;
    /*
     * 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
     */

    /*
     * Attempt to get the fixed panel mode from DDC.  Assume that the
     * preferred mode is the right one.
     */
    intel_lvds->edid = drm_get_edid(connector,
                    intel_gmbus_get_adapter(dev_priv,
                                pin));
    if (intel_lvds->edid) {
        if (drm_add_edid_modes(connector,
                       intel_lvds->edid)) {
            drm_mode_connector_update_edid_property(connector,
                                intel_lvds->edid);
        } else {
            kfree(intel_lvds->edid);
            intel_lvds->edid = NULL;
        }
    }
    if (!intel_lvds->edid) {
        /* Didn't get an EDID, so
         * Set wide sync ranges so we get all modes
         * handed to valid_mode for checking
         */
        connector->display_info.min_vfreq = 0;
        connector->display_info.max_vfreq = 200;
        connector->display_info.min_hfreq = 0;
        connector->display_info.max_hfreq = 200;
    }

    list_for_each_entry(scan, &connector->probed_modes, head) {
        if (scan->type & DRM_MODE_TYPE_PREFERRED) {
            intel_lvds->fixed_mode =
                drm_mode_duplicate(dev, scan);
            intel_find_lvds_downclock(dev,
                          intel_lvds->fixed_mode,
                          connector);
            goto out;
        }
    }

    /* Failed to get EDID, what about VBT? */
    if (dev_priv->lfp_lvds_vbt_mode) {
        intel_lvds->fixed_mode =
            drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
        if (intel_lvds->fixed_mode) {
            intel_lvds->fixed_mode->type |=
                DRM_MODE_TYPE_PREFERRED;
            goto out;
        }
    }

    /*
     * 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.
     */

    /* Ironlake: FIXME if still fail, not try pipe mode now */
    if (HAS_PCH_SPLIT(dev))
        goto failed;

    lvds = I915_READ(LVDS);
    pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
    crtc = intel_get_crtc_for_pipe(dev, pipe);

    if (crtc && (lvds & LVDS_PORT_EN)) {
        intel_lvds->fixed_mode = intel_crtc_mode_get(dev, crtc);
        if (intel_lvds->fixed_mode) {
            intel_lvds->fixed_mode->type |=
                DRM_MODE_TYPE_PREFERRED;
            goto out;
        }
    }

    /* If we still don't have a mode after all that, give up. */
    if (!intel_lvds->fixed_mode)
        goto failed;

out:
    /*
     * Unlock registers and just
     * leave them unlocked
     */
    if (HAS_PCH_SPLIT(dev)) {
        I915_WRITE(PCH_PP_CONTROL,
               I915_READ(PCH_PP_CONTROL) | PANEL_UNLOCK_REGS);
    } else {
        I915_WRITE(PP_CONTROL,
               I915_READ(PP_CONTROL) | PANEL_UNLOCK_REGS);
    }
    dev_priv->lid_notifier.notifier_call = intel_lid_notify;
    if (acpi_lid_notifier_register(&dev_priv->lid_notifier)) {
        DRM_DEBUG_KMS("lid notifier registration failed\n");
        dev_priv->lid_notifier.notifier_call = NULL;
    }
    /* keep the LVDS connector */
    dev_priv->int_lvds_connector = connector;
    drm_sysfs_connector_add(connector);

    intel_panel_setup_backlight(dev);

    return true;

failed:
    DRM_DEBUG_KMS("No LVDS modes found, disabling.\n");
    drm_connector_cleanup(connector);
    drm_encoder_cleanup(encoder);
    kfree(intel_lvds);
    kfree(intel_connector);
    return false;
}