Quelle  intel_crt.c   Sprache: C

/*
 * Copyright © 2006-2007 Intel Corporation
 *
 * 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 <eric@anholt.net>
 */

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

#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

#include "intel_connector.h"
#include "intel_crt.h"
#include "intel_crt_regs.h"
#include "intel_crtc.h"
#include "intel_ddi.h"
#include "intel_ddi_buf_trans.h"
#include "intel_de.h"
#include "intel_display_driver.h"
#include "intel_display_regs.h"
#include "intel_display_types.h"
#include "intel_fdi.h"
#include "intel_fdi_regs.h"
#include "intel_fifo_underrun.h"
#include "intel_gmbus.h"
#include "intel_hotplug.h"
#include "intel_hotplug_irq.h"
#include "intel_load_detect.h"
#include "intel_pch_display.h"
#include "intel_pch_refclk.h"
#include "intel_pfit.h"

/* Here's the desired hotplug mode */
#define ADPA_HOTPLUG_BITS (ADPA_CRT_HOTPLUG_ENABLE |   \
      ADPA_CRT_HOTPLUG_PERIOD_128 |  \
      ADPA_CRT_HOTPLUG_WARMUP_10MS |  \
      ADPA_CRT_HOTPLUG_SAMPLE_4S |   \
      ADPA_CRT_HOTPLUG_VOLTAGE_50 |  \
      ADPA_CRT_HOTPLUG_VOLREF_325MV)
#define ADPA_HOTPLUG_MASK (ADPA_CRT_HOTPLUG_MONITOR_MASK |  \
      ADPA_CRT_HOTPLUG_ENABLE |   \
      ADPA_CRT_HOTPLUG_PERIOD_MASK |  \
      ADPA_CRT_HOTPLUG_WARMUP_MASK |  \
      ADPA_CRT_HOTPLUG_SAMPLE_MASK |  \
      ADPA_CRT_HOTPLUG_VOLTAGE_MASK |  \
      ADPA_CRT_HOTPLUG_VOLREF_MASK |  \
      ADPA_CRT_HOTPLUG_FORCE_TRIGGER)

struct intel_crt {
 struct intel_encoder base;
 bool force_hotplug_required;
 i915_reg_t adpa_reg;
};

static struct intel_crt *intel_encoder_to_crt(struct intel_encoder *encoder)
{
 return container_of(encoder, struct intel_crt, base);
}

static struct intel_crt *intel_attached_crt(struct intel_connector *connector)
{
 return intel_encoder_to_crt(intel_attached_encoder(connector));
}

bool intel_crt_port_enabled(struct intel_display *display,
       i915_reg_t adpa_reg, enum pipe *pipe)
{
 u32 val;

 val = intel_de_read(display, adpa_reg);

 /* asserts want to know the pipe even if the port is disabled */
 if (HAS_PCH_CPT(display))
  *pipe = REG_FIELD_GET(ADPA_PIPE_SEL_MASK_CPT, val);
 else
  *pipe = REG_FIELD_GET(ADPA_PIPE_SEL_MASK, val);

 return val & ADPA_DAC_ENABLE;
}

static bool intel_crt_get_hw_state(struct intel_encoder *encoder,
       enum pipe *pipe)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crt *crt = intel_encoder_to_crt(encoder);
 intel_wakeref_t wakeref;
 bool ret;

 wakeref = intel_display_power_get_if_enabled(display,
           encoder->power_domain);
 if (!wakeref)
  return false;

 ret = intel_crt_port_enabled(display, crt->adpa_reg, pipe);

 intel_display_power_put(display, encoder->power_domain, wakeref);

 return ret;
}

static unsigned int intel_crt_get_flags(struct intel_encoder *encoder)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crt *crt = intel_encoder_to_crt(encoder);
 u32 tmp, flags = 0;

 tmp = intel_de_read(display, crt->adpa_reg);

 if (tmp & ADPA_HSYNC_ACTIVE_HIGH)
  flags |= DRM_MODE_FLAG_PHSYNC;
 else
  flags |= DRM_MODE_FLAG_NHSYNC;

 if (tmp & ADPA_VSYNC_ACTIVE_HIGH)
  flags |= DRM_MODE_FLAG_PVSYNC;
 else
  flags |= DRM_MODE_FLAG_NVSYNC;

 return flags;
}

static void intel_crt_get_config(struct intel_encoder *encoder,
     struct intel_crtc_state *crtc_state)
{
 crtc_state->output_types |= BIT(INTEL_OUTPUT_ANALOG);

 crtc_state->hw.adjusted_mode.flags |= intel_crt_get_flags(encoder);

 crtc_state->hw.adjusted_mode.crtc_clock = crtc_state->port_clock;
}

static void hsw_crt_get_config(struct intel_encoder *encoder,
          struct intel_crtc_state *crtc_state)
{
 lpt_pch_get_config(crtc_state);

 hsw_ddi_get_config(encoder, crtc_state);

 crtc_state->hw.adjusted_mode.flags &= ~(DRM_MODE_FLAG_PHSYNC |
      DRM_MODE_FLAG_NHSYNC |
      DRM_MODE_FLAG_PVSYNC |
      DRM_MODE_FLAG_NVSYNC);
 crtc_state->hw.adjusted_mode.flags |= intel_crt_get_flags(encoder);
}

/* Note: The caller is required to filter out dpms modes not supported by the
 * platform. */
static void intel_crt_set_dpms(struct intel_encoder *encoder,
          const struct intel_crtc_state *crtc_state,
          int mode)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crt *crt = intel_encoder_to_crt(encoder);
 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
 u32 adpa;

 if (DISPLAY_VER(display) >= 5)
  adpa = ADPA_HOTPLUG_BITS;
 else
  adpa = 0;

 if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
  adpa |= ADPA_HSYNC_ACTIVE_HIGH;
 if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
  adpa |= ADPA_VSYNC_ACTIVE_HIGH;

 /* For CPT allow 3 pipe config, for others just use A or B */
 if (HAS_PCH_LPT(display))
  ; /* Those bits don't exist here */
 else if (HAS_PCH_CPT(display))
  adpa |= ADPA_PIPE_SEL_CPT(crtc->pipe);
 else
  adpa |= ADPA_PIPE_SEL(crtc->pipe);

 if (!HAS_PCH_SPLIT(display))
  intel_de_write(display, BCLRPAT(display, crtc->pipe), 0);

 switch (mode) {
 case DRM_MODE_DPMS_ON:
  adpa |= ADPA_DAC_ENABLE;
  break;
 case DRM_MODE_DPMS_STANDBY:
  adpa |= ADPA_DAC_ENABLE | ADPA_HSYNC_CNTL_DISABLE;
  break;
 case DRM_MODE_DPMS_SUSPEND:
  adpa |= ADPA_DAC_ENABLE | ADPA_VSYNC_CNTL_DISABLE;
  break;
 case DRM_MODE_DPMS_OFF:
  adpa |= ADPA_HSYNC_CNTL_DISABLE | ADPA_VSYNC_CNTL_DISABLE;
  break;
 }

 intel_de_write(display, crt->adpa_reg, adpa);
}

static void intel_disable_crt(struct intel_atomic_state *state,
         struct intel_encoder *encoder,
         const struct intel_crtc_state *old_crtc_state,
         const struct drm_connector_state *old_conn_state)
{
 intel_crt_set_dpms(encoder, old_crtc_state, DRM_MODE_DPMS_OFF);
}

static void pch_disable_crt(struct intel_atomic_state *state,
       struct intel_encoder *encoder,
       const struct intel_crtc_state *old_crtc_state,
       const struct drm_connector_state *old_conn_state)
{
}

static void pch_post_disable_crt(struct intel_atomic_state *state,
     struct intel_encoder *encoder,
     const struct intel_crtc_state *old_crtc_state,
     const struct drm_connector_state *old_conn_state)
{
 intel_disable_crt(state, encoder, old_crtc_state, old_conn_state);
}

static void hsw_disable_crt(struct intel_atomic_state *state,
       struct intel_encoder *encoder,
       const struct intel_crtc_state *old_crtc_state,
       const struct drm_connector_state *old_conn_state)
{
 struct intel_display *display = to_intel_display(encoder);

 drm_WARN_ON(display->drm, !old_crtc_state->has_pch_encoder);

 intel_set_pch_fifo_underrun_reporting(display, PIPE_A, false);
}

static void hsw_post_disable_crt(struct intel_atomic_state *state,
     struct intel_encoder *encoder,
     const struct intel_crtc_state *old_crtc_state,
     const struct drm_connector_state *old_conn_state)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);

 intel_crtc_vblank_off(old_crtc_state);

 intel_disable_transcoder(old_crtc_state);

 intel_ddi_disable_transcoder_func(old_crtc_state);

 ilk_pfit_disable(old_crtc_state);

 intel_ddi_disable_transcoder_clock(old_crtc_state);

 pch_post_disable_crt(state, encoder, old_crtc_state, old_conn_state);

 lpt_pch_disable(state, crtc);

 hsw_fdi_disable(encoder);

 drm_WARN_ON(display->drm, !old_crtc_state->has_pch_encoder);

 intel_set_pch_fifo_underrun_reporting(display, PIPE_A, true);
}

static void hsw_pre_pll_enable_crt(struct intel_atomic_state *state,
       struct intel_encoder *encoder,
       const struct intel_crtc_state *crtc_state,
       const struct drm_connector_state *conn_state)
{
 struct intel_display *display = to_intel_display(encoder);

 drm_WARN_ON(display->drm, !crtc_state->has_pch_encoder);

 intel_set_pch_fifo_underrun_reporting(display, PIPE_A, false);
}

static void hsw_pre_enable_crt(struct intel_atomic_state *state,
          struct intel_encoder *encoder,
          const struct intel_crtc_state *crtc_state,
          const struct drm_connector_state *conn_state)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 enum pipe pipe = crtc->pipe;

 drm_WARN_ON(display->drm, !crtc_state->has_pch_encoder);

 intel_set_cpu_fifo_underrun_reporting(display, pipe, false);

 hsw_fdi_link_train(encoder, crtc_state);

 intel_ddi_enable_transcoder_clock(encoder, crtc_state);
}

static void hsw_enable_crt(struct intel_atomic_state *state,
      struct intel_encoder *encoder,
      const struct intel_crtc_state *crtc_state,
      const struct drm_connector_state *conn_state)
{
 struct intel_display *display = to_intel_display(encoder);
 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 enum pipe pipe = crtc->pipe;

 drm_WARN_ON(display->drm, !crtc_state->has_pch_encoder);

 intel_ddi_enable_transcoder_func(encoder, crtc_state);

 intel_enable_transcoder(crtc_state);

 lpt_pch_enable(state, crtc);

 intel_crtc_vblank_on(crtc_state);

 intel_crt_set_dpms(encoder, crtc_state, DRM_MODE_DPMS_ON);

 intel_crtc_wait_for_next_vblank(crtc);
 intel_crtc_wait_for_next_vblank(crtc);
 intel_set_cpu_fifo_underrun_reporting(display, pipe, true);
 intel_set_pch_fifo_underrun_reporting(display, PIPE_A, true);
}

static void intel_enable_crt(struct intel_atomic_state *state,
        struct intel_encoder *encoder,
        const struct intel_crtc_state *crtc_state,
        const struct drm_connector_state *conn_state)
{
 intel_crt_set_dpms(encoder, crtc_state, DRM_MODE_DPMS_ON);
}

static enum drm_mode_status
intel_crt_mode_valid(struct drm_connector *connector,
       const struct drm_display_mode *mode)
{
 struct intel_display *display = to_intel_display(connector->dev);
 int max_dotclk = display->cdclk.max_dotclk_freq;
 enum drm_mode_status status;
 int max_clock;

 status = intel_cpu_transcoder_mode_valid(display, mode);
 if (status != MODE_OK)
  return status;

 if (mode->clock < 25000)
  return MODE_CLOCK_LOW;

 if (HAS_PCH_LPT(display))
  max_clock = 180000;
 else if (display->platform.valleyview)
  /*
 * 270 MHz due to current DPLL limits,
 * DAC limit supposedly 355 MHz.
 */
  max_clock = 270000;
 else if (IS_DISPLAY_VER(display, 3, 4))
  max_clock = 400000;
 else
  max_clock = 350000;
 if (mode->clock > max_clock)
  return MODE_CLOCK_HIGH;

 if (mode->clock > max_dotclk)
  return MODE_CLOCK_HIGH;

 /* The FDI receiver on LPT only supports 8bpc and only has 2 lanes. */
 if (HAS_PCH_LPT(display) &&
     ilk_get_lanes_required(mode->clock, 270000, 24) > 2)
  return MODE_CLOCK_HIGH;

 /* HSW/BDW FDI limited to 4k */
 if (mode->hdisplay > 4096)
  return MODE_H_ILLEGAL;

 return MODE_OK;
}

static int intel_crt_compute_config(struct intel_encoder *encoder,
        struct intel_crtc_state *crtc_state,
        struct drm_connector_state *conn_state)
{
 struct drm_display_mode *adjusted_mode =
  &crtc_state->hw.adjusted_mode;

 if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
  return -EINVAL;

 crtc_state->sink_format = INTEL_OUTPUT_FORMAT_RGB;
 crtc_state->output_format = INTEL_OUTPUT_FORMAT_RGB;

 return 0;
}

static int pch_crt_compute_config(struct intel_encoder *encoder,
      struct intel_crtc_state *crtc_state,
      struct drm_connector_state *conn_state)
{
 struct drm_display_mode *adjusted_mode =
  &crtc_state->hw.adjusted_mode;

 if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
  return -EINVAL;

 crtc_state->has_pch_encoder = true;
 if (!intel_fdi_compute_pipe_bpp(crtc_state))
  return -EINVAL;

 crtc_state->output_format = INTEL_OUTPUT_FORMAT_RGB;

 return 0;
}

static int hsw_crt_compute_config(struct intel_encoder *encoder,
      struct intel_crtc_state *crtc_state,
      struct drm_connector_state *conn_state)
{
 struct intel_display *display = to_intel_display(encoder);
 struct drm_display_mode *adjusted_mode =
  &crtc_state->hw.adjusted_mode;

 if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
  return -EINVAL;

 /* HSW/BDW FDI limited to 4k */
 if (adjusted_mode->crtc_hdisplay > 4096 ||
     adjusted_mode->crtc_hblank_start > 4096)
  return -EINVAL;

 crtc_state->has_pch_encoder = true;
 if (!intel_fdi_compute_pipe_bpp(crtc_state))
  return -EINVAL;

 crtc_state->output_format = INTEL_OUTPUT_FORMAT_RGB;

 /* LPT FDI RX only supports 8bpc. */
 if (HAS_PCH_LPT(display)) {
  /* TODO: Check crtc_state->max_link_bpp_x16 instead of bw_constrained */
  if (crtc_state->bw_constrained && crtc_state->pipe_bpp < 24) {
   drm_dbg_kms(display->drm,
        "LPT only supports 24bpp\n");
   return -EINVAL;
  }

  crtc_state->pipe_bpp = 24;
 }

 /* FDI must always be 2.7 GHz */
 crtc_state->port_clock = 135000 * 2;

 crtc_state->enhanced_framing = true;

 adjusted_mode->crtc_clock = lpt_iclkip(crtc_state);

 return 0;
}

static bool ilk_crt_detect_hotplug(struct drm_connector *connector)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_crt *crt = intel_attached_crt(to_intel_connector(connector));
 u32 adpa;
 bool ret;

 /* The first time through, trigger an explicit detection cycle */
 if (crt->force_hotplug_required) {
  bool turn_off_dac = HAS_PCH_SPLIT(display);
  u32 save_adpa;

  crt->force_hotplug_required = false;

  save_adpa = adpa = intel_de_read(display, crt->adpa_reg);
  drm_dbg_kms(display->drm,
       "trigger hotplug detect cycle: adpa=0x%x\n", adpa);

  adpa |= ADPA_CRT_HOTPLUG_FORCE_TRIGGER;
  if (turn_off_dac)
   adpa &= ~ADPA_DAC_ENABLE;

  intel_de_write(display, crt->adpa_reg, adpa);

  if (intel_de_wait_for_clear(display,
         crt->adpa_reg,
         ADPA_CRT_HOTPLUG_FORCE_TRIGGER,
         1000))
   drm_dbg_kms(display->drm,
        "timed out waiting for FORCE_TRIGGER");

  if (turn_off_dac) {
   intel_de_write(display, crt->adpa_reg, save_adpa);
   intel_de_posting_read(display, crt->adpa_reg);
  }
 }

 /* Check the status to see if both blue and green are on now */
 adpa = intel_de_read(display, crt->adpa_reg);
 if ((adpa & ADPA_CRT_HOTPLUG_MONITOR_MASK) != 0)
  ret = true;
 else
  ret = false;
 drm_dbg_kms(display->drm, "ironlake hotplug adpa=0x%x, result %d\n",
      adpa, ret);

 return ret;
}

static bool valleyview_crt_detect_hotplug(struct drm_connector *connector)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_crt *crt = intel_attached_crt(to_intel_connector(connector));
 u32 adpa;
 bool ret;
 u32 save_adpa;

 /*
 * Doing a force trigger causes a hpd interrupt to get sent, which can
 * get us stuck in a loop if we're polling:
 *  - We enable power wells and reset the ADPA
 *  - output_poll_exec does force probe on VGA, triggering a hpd
 *  - HPD handler waits for poll to unlock dev->mode_config.mutex
 *  - output_poll_exec shuts off the ADPA, unlocks
 *    dev->mode_config.mutex
 *  - HPD handler runs, resets ADPA and brings us back to the start
 *
 * Just disable HPD interrupts here to prevent this
 */
 intel_hpd_block(&crt->base);

 save_adpa = adpa = intel_de_read(display, crt->adpa_reg);
 drm_dbg_kms(display->drm,
      "trigger hotplug detect cycle: adpa=0x%x\n", adpa);

 adpa |= ADPA_CRT_HOTPLUG_FORCE_TRIGGER;

 intel_de_write(display, crt->adpa_reg, adpa);

 if (intel_de_wait_for_clear(display, crt->adpa_reg,
        ADPA_CRT_HOTPLUG_FORCE_TRIGGER, 1000)) {
  drm_dbg_kms(display->drm,
       "timed out waiting for FORCE_TRIGGER");
  intel_de_write(display, crt->adpa_reg, save_adpa);
 }

 /* Check the status to see if both blue and green are on now */
 adpa = intel_de_read(display, crt->adpa_reg);
 if ((adpa & ADPA_CRT_HOTPLUG_MONITOR_MASK) != 0)
  ret = true;
 else
  ret = false;

 drm_dbg_kms(display->drm,
      "valleyview hotplug adpa=0x%x, result %d\n", adpa, ret);

 intel_hpd_clear_and_unblock(&crt->base);

 return ret;
}

static bool intel_crt_detect_hotplug(struct drm_connector *connector)
{
 struct intel_display *display = to_intel_display(connector->dev);
 u32 stat;
 bool ret = false;
 int i, tries = 0;

 if (HAS_PCH_SPLIT(display))
  return ilk_crt_detect_hotplug(connector);

 if (display->platform.valleyview)
  return valleyview_crt_detect_hotplug(connector);

 /*
 * On 4 series desktop, CRT detect sequence need to be done twice
 * to get a reliable result.
 */

 if (display->platform.g45)
  tries = 2;
 else
  tries = 1;

 for (i = 0; i < tries ; i++) {
  /* turn on the FORCE_DETECT */
  i915_hotplug_interrupt_update(display,
           CRT_HOTPLUG_FORCE_DETECT,
           CRT_HOTPLUG_FORCE_DETECT);
  /* wait for FORCE_DETECT to go off */
  if (intel_de_wait_for_clear(display, PORT_HOTPLUG_EN(display),
         CRT_HOTPLUG_FORCE_DETECT, 1000))
   drm_dbg_kms(display->drm,
        "timed out waiting for FORCE_DETECT to go off");
 }

 stat = intel_de_read(display, PORT_HOTPLUG_STAT(display));
 if ((stat & CRT_HOTPLUG_MONITOR_MASK) != CRT_HOTPLUG_MONITOR_NONE)
  ret = true;

 /* clear the interrupt we just generated, if any */
 intel_de_write(display, PORT_HOTPLUG_STAT(display),
         CRT_HOTPLUG_INT_STATUS);

 i915_hotplug_interrupt_update(display, CRT_HOTPLUG_FORCE_DETECT, 0);

 return ret;
}

static const struct drm_edid *intel_crt_get_edid(struct drm_connector *connector,
       struct i2c_adapter *ddc)
{
 const struct drm_edid *drm_edid;

 drm_edid = drm_edid_read_ddc(connector, ddc);

 if (!drm_edid && !intel_gmbus_is_forced_bit(ddc)) {
  drm_dbg_kms(connector->dev,
       "CRT GMBUS EDID read failed, retry using GPIO bit-banging\n");
  intel_gmbus_force_bit(ddc, true);
  drm_edid = drm_edid_read_ddc(connector, ddc);
  intel_gmbus_force_bit(ddc, false);
 }

 return drm_edid;
}

/* local version of intel_ddc_get_modes() to use intel_crt_get_edid() */
static int intel_crt_ddc_get_modes(struct drm_connector *connector,
       struct i2c_adapter *ddc)
{
 const struct drm_edid *drm_edid;
 int ret;

 drm_edid = intel_crt_get_edid(connector, ddc);
 if (!drm_edid)
  return 0;

 ret = intel_connector_update_modes(connector, drm_edid);

 drm_edid_free(drm_edid);

 return ret;
}

static bool intel_crt_detect_ddc(struct drm_connector *connector)
{
 struct intel_display *display = to_intel_display(connector->dev);
 const struct drm_edid *drm_edid;
 bool ret = false;

 drm_edid = intel_crt_get_edid(connector, connector->ddc);

 if (drm_edid) {
  /*
 * This may be a DVI-I connector with a shared DDC
 * link between analog and digital outputs, so we
 * have to check the EDID input spec of the attached device.
 */
  if (drm_edid_is_digital(drm_edid)) {
   drm_dbg_kms(display->drm,
        "CRT not detected via DDC:0x50 [EDID reports a digital panel]\n");
  } else {
   drm_dbg_kms(display->drm,
        "CRT detected via DDC:0x50 [EDID]\n");
   ret = true;
  }
 } else {
  drm_dbg_kms(display->drm,
       "CRT not detected via DDC:0x50 [no valid EDID found]\n");
 }

 drm_edid_free(drm_edid);

 return ret;
}

static enum drm_connector_status
intel_crt_load_detect(struct intel_crt *crt, enum pipe pipe)
{
 struct intel_display *display = to_intel_display(&crt->base);
 enum transcoder cpu_transcoder = (enum transcoder)pipe;
 u32 save_bclrpat;
 u32 save_vtotal;
 u32 vtotal, vactive;
 u32 vsample;
 u32 vblank, vblank_start, vblank_end;
 u32 dsl;
 u8 st00;
 enum drm_connector_status status;

 drm_dbg_kms(display->drm, "starting load-detect on CRT\n");

 save_bclrpat = intel_de_read(display,
         BCLRPAT(display, cpu_transcoder));
 save_vtotal = intel_de_read(display,
        TRANS_VTOTAL(display, cpu_transcoder));
 vblank = intel_de_read(display,
          TRANS_VBLANK(display, cpu_transcoder));

 vtotal = REG_FIELD_GET(VTOTAL_MASK, save_vtotal) + 1;
 vactive = REG_FIELD_GET(VACTIVE_MASK, save_vtotal) + 1;

 vblank_start = REG_FIELD_GET(VBLANK_START_MASK, vblank) + 1;
 vblank_end = REG_FIELD_GET(VBLANK_END_MASK, vblank) + 1;

 /* Set the border color to purple. */
 intel_de_write(display, BCLRPAT(display, cpu_transcoder), 0x500050);

 if (DISPLAY_VER(display) != 2) {
  u32 transconf = intel_de_read(display,
           TRANSCONF(display, cpu_transcoder));

  intel_de_write(display, TRANSCONF(display, cpu_transcoder),
          transconf | TRANSCONF_FORCE_BORDER);
  intel_de_posting_read(display,
          TRANSCONF(display, cpu_transcoder));
  /*
 * Wait for next Vblank to substitute
 * border color for Color info.
 */
  intel_crtc_wait_for_next_vblank(intel_crtc_for_pipe(display, pipe));
  st00 = intel_de_read8(display, _VGA_MSR_WRITE);
  status = ((st00 & (1 << 4)) != 0) ?
   connector_status_connected :
   connector_status_disconnected;

  intel_de_write(display, TRANSCONF(display, cpu_transcoder),
          transconf);
 } else {
  bool restore_vblank = false;
  int count, detect;

  /*
* If there isn't any border, add some.
* Yes, this will flicker
*/
  if (vblank_start <= vactive && vblank_end >= vtotal) {
   u32 vsync = intel_de_read(display,
        TRANS_VSYNC(display, cpu_transcoder));
   u32 vsync_start = REG_FIELD_GET(VSYNC_START_MASK, vsync) + 1;

   vblank_start = vsync_start;
   intel_de_write(display,
           TRANS_VBLANK(display, cpu_transcoder),
           VBLANK_START(vblank_start - 1) |
           VBLANK_END(vblank_end - 1));
   restore_vblank = true;
  }
  /* sample in the vertical border, selecting the larger one */
  if (vblank_start - vactive >= vtotal - vblank_end)
   vsample = (vblank_start + vactive) >> 1;
  else
   vsample = (vtotal + vblank_end) >> 1;

  /*
 * Wait for the border to be displayed
 */
  while (intel_de_read(display, PIPEDSL(display, pipe)) >= vactive)
   ;
  while ((dsl = intel_de_read(display, PIPEDSL(display, pipe))) <= vsample)
   ;
  /*
 * Watch ST00 for an entire scanline
 */
  detect = 0;
  count = 0;
  do {
   count++;
   /* Read the ST00 VGA status register */
   st00 = intel_de_read8(display, _VGA_MSR_WRITE);
   if (st00 & (1 << 4))
    detect++;
  } while ((intel_de_read(display, PIPEDSL(display, pipe)) == dsl));

  /* restore vblank if necessary */
  if (restore_vblank)
   intel_de_write(display,
           TRANS_VBLANK(display, cpu_transcoder),
           vblank);
  /*
 * If more than 3/4 of the scanline detected a monitor,
 * then it is assumed to be present. This works even on i830,
 * where there isn't any way to force the border color across
 * the screen
 */
  status = detect * 4 > count * 3 ?
    connector_status_connected :
    connector_status_disconnected;
 }

 /* Restore previous settings */
 intel_de_write(display, BCLRPAT(display, cpu_transcoder),
         save_bclrpat);

 return status;
}

static int intel_spurious_crt_detect_dmi_callback(const struct dmi_system_id *id)
{
 DRM_DEBUG_DRIVER("Skipping CRT detection for %s\n", id->ident);
 return 1;
}

static const struct dmi_system_id intel_spurious_crt_detect[] = {
 {
  .callback = intel_spurious_crt_detect_dmi_callback,
  .ident = "ACER ZGB",
  .matches = {
   DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
   DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
  },
 },
 {
  .callback = intel_spurious_crt_detect_dmi_callback,
  .ident = "Intel DZ77BH-55K",
  .matches = {
   DMI_MATCH(DMI_BOARD_VENDOR, "Intel Corporation"),
   DMI_MATCH(DMI_BOARD_NAME, "DZ77BH-55K"),
  },
 },
 { }
};

static int
intel_crt_detect(struct drm_connector *connector,
   struct drm_modeset_acquire_ctx *ctx,
   bool force)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_crt *crt = intel_attached_crt(to_intel_connector(connector));
 struct intel_encoder *encoder = &crt->base;
 struct drm_atomic_state *state;
 intel_wakeref_t wakeref;
 int status;

 drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s] force=%d\n",
      connector->base.id, connector->name,
      force);

 if (!intel_display_device_enabled(display))
  return connector_status_disconnected;

 if (!intel_display_driver_check_access(display))
  return connector->status;

 if (display->params.load_detect_test) {
  wakeref = intel_display_power_get(display, encoder->power_domain);
  goto load_detect;
 }

 /* Skip machines without VGA that falsely report hotplug events */
 if (dmi_check_system(intel_spurious_crt_detect))
  return connector_status_disconnected;

 wakeref = intel_display_power_get(display, encoder->power_domain);

 if (HAS_HOTPLUG(display)) {
  /* We can not rely on the HPD pin always being correctly wired
 * up, for example many KVM do not pass it through, and so
 * only trust an assertion that the monitor is connected.
 */
  if (intel_crt_detect_hotplug(connector)) {
   drm_dbg_kms(display->drm,
        "CRT detected via hotplug\n");
   status = connector_status_connected;
   goto out;
  } else
   drm_dbg_kms(display->drm,
        "CRT not detected via hotplug\n");
 }

 if (intel_crt_detect_ddc(connector)) {
  status = connector_status_connected;
  goto out;
 }

 /* Load detection is broken on HPD capable machines. Whoever wants a
 * broken monitor (without edid) to work behind a broken kvm (that fails
 * to have the right resistors for HP detection) needs to fix this up.
 * For now just bail out. */
 if (HAS_HOTPLUG(display)) {
  status = connector_status_disconnected;
  goto out;
 }

load_detect:
 if (!force) {
  status = connector->status;
  goto out;
 }

 /* for pre-945g platforms use load detect */
 state = intel_load_detect_get_pipe(connector, ctx);
 if (IS_ERR(state)) {
  status = PTR_ERR(state);
 } else if (!state) {
  status = connector_status_unknown;
 } else {
  if (intel_crt_detect_ddc(connector))
   status = connector_status_connected;
  else if (DISPLAY_VER(display) < 4)
   status = intel_crt_load_detect(crt,
    to_intel_crtc(connector->state->crtc)->pipe);
  else if (display->params.load_detect_test)
   status = connector_status_disconnected;
  else
   status = connector_status_unknown;
  intel_load_detect_release_pipe(connector, state, ctx);
 }

out:
 intel_display_power_put(display, encoder->power_domain, wakeref);

 return status;
}

static int intel_crt_get_modes(struct drm_connector *connector)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_crt *crt = intel_attached_crt(to_intel_connector(connector));
 struct intel_encoder *encoder = &crt->base;
 intel_wakeref_t wakeref;
 struct i2c_adapter *ddc;
 int ret;

 if (!intel_display_driver_check_access(display))
  return drm_edid_connector_add_modes(connector);

 wakeref = intel_display_power_get(display, encoder->power_domain);

 ret = intel_crt_ddc_get_modes(connector, connector->ddc);
 if (ret || !display->platform.g4x)
  goto out;

 /* Try to probe digital port for output in DVI-I -> VGA mode. */
 ddc = intel_gmbus_get_adapter(display, GMBUS_PIN_DPB);
 ret = intel_crt_ddc_get_modes(connector, ddc);

out:
 intel_display_power_put(display, encoder->power_domain, wakeref);

 return ret;
}

void intel_crt_reset(struct drm_encoder *encoder)
{
 struct intel_display *display = to_intel_display(encoder->dev);
 struct intel_crt *crt = intel_encoder_to_crt(to_intel_encoder(encoder));

 if (DISPLAY_VER(display) >= 5) {
  u32 adpa;

  adpa = intel_de_read(display, crt->adpa_reg);
  adpa &= ~ADPA_HOTPLUG_MASK;
  adpa |= ADPA_HOTPLUG_BITS;
  intel_de_write(display, crt->adpa_reg, adpa);
  intel_de_posting_read(display, crt->adpa_reg);

  drm_dbg_kms(display->drm, "crt adpa set to 0x%x\n", adpa);
  crt->force_hotplug_required = true;
 }

}

/*
 * Routines for controlling stuff on the analog port
 */

static const struct drm_connector_funcs intel_crt_connector_funcs = {
 .fill_modes = drm_helper_probe_single_connector_modes,
 .late_register = intel_connector_register,
 .early_unregister = intel_connector_unregister,
 .destroy = intel_connector_destroy,
 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
};

static const struct drm_connector_helper_funcs intel_crt_connector_helper_funcs = {
 .detect_ctx = intel_crt_detect,
 .mode_valid = intel_crt_mode_valid,
 .get_modes = intel_crt_get_modes,
};

static const struct drm_encoder_funcs intel_crt_enc_funcs = {
 .reset = intel_crt_reset,
 .destroy = intel_encoder_destroy,
};

void intel_crt_init(struct intel_display *display)
{
 struct intel_connector *connector;
 struct intel_crt *crt;
 i915_reg_t adpa_reg;
 u8 ddc_pin;
 u32 adpa;

 if (HAS_PCH_SPLIT(display))
  adpa_reg = PCH_ADPA;
 else if (display->platform.valleyview)
  adpa_reg = VLV_ADPA;
 else
  adpa_reg = ADPA;

 adpa = intel_de_read(display, adpa_reg);
 if ((adpa & ADPA_DAC_ENABLE) == 0) {
  /*
 * On some machines (some IVB at least) CRT can be
 * fused off, but there's no known fuse bit to
 * indicate that. On these machine the ADPA register
 * works normally, except the DAC enable bit won't
 * take. So the only way to tell is attempt to enable
 * it and see what happens.
 */
  intel_de_write(display, adpa_reg,
          adpa | ADPA_DAC_ENABLE |
          ADPA_HSYNC_CNTL_DISABLE |
          ADPA_VSYNC_CNTL_DISABLE);
  if ((intel_de_read(display, adpa_reg) & ADPA_DAC_ENABLE) == 0)
   return;
  intel_de_write(display, adpa_reg, adpa);
 }

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

 connector = intel_connector_alloc();
 if (!connector) {
  kfree(crt);
  return;
 }

 ddc_pin = display->vbt.crt_ddc_pin;

 drm_connector_init_with_ddc(display->drm, &connector->base,
        &intel_crt_connector_funcs,
        DRM_MODE_CONNECTOR_VGA,
        intel_gmbus_get_adapter(display, ddc_pin));

 drm_encoder_init(display->drm, &crt->base.base, &intel_crt_enc_funcs,
    DRM_MODE_ENCODER_DAC, "CRT");

 intel_connector_attach_encoder(connector, &crt->base);

 crt->base.type = INTEL_OUTPUT_ANALOG;
 crt->base.cloneable = BIT(INTEL_OUTPUT_DVO) | BIT(INTEL_OUTPUT_HDMI);
 if (display->platform.i830)
  crt->base.pipe_mask = BIT(PIPE_A);
 else
  crt->base.pipe_mask = ~0;

 if (DISPLAY_VER(display) != 2)
  connector->base.interlace_allowed = true;

 crt->adpa_reg = adpa_reg;

 crt->base.power_domain = POWER_DOMAIN_PORT_CRT;

 if (HAS_HOTPLUG(display) &&
     !dmi_check_system(intel_spurious_crt_detect)) {
  crt->base.hpd_pin = HPD_CRT;
  crt->base.hotplug = intel_encoder_hotplug;
  connector->polled = DRM_CONNECTOR_POLL_HPD;
 } else {
  connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 }
 connector->base.polled = connector->polled;

 if (HAS_DDI(display)) {
  assert_port_valid(display, PORT_E);

  crt->base.port = PORT_E;
  crt->base.get_config = hsw_crt_get_config;
  crt->base.get_hw_state = intel_ddi_get_hw_state;
  crt->base.compute_config = hsw_crt_compute_config;
  crt->base.pre_pll_enable = hsw_pre_pll_enable_crt;
  crt->base.pre_enable = hsw_pre_enable_crt;
  crt->base.enable = hsw_enable_crt;
  crt->base.disable = hsw_disable_crt;
  crt->base.post_disable = hsw_post_disable_crt;
  crt->base.enable_clock = hsw_ddi_enable_clock;
  crt->base.disable_clock = hsw_ddi_disable_clock;
  crt->base.is_clock_enabled = hsw_ddi_is_clock_enabled;

  intel_ddi_buf_trans_init(&crt->base);
 } else {
  if (HAS_PCH_SPLIT(display)) {
   crt->base.compute_config = pch_crt_compute_config;
   crt->base.disable = pch_disable_crt;
   crt->base.post_disable = pch_post_disable_crt;
  } else {
   crt->base.compute_config = intel_crt_compute_config;
   crt->base.disable = intel_disable_crt;
  }
  crt->base.port = PORT_NONE;
  crt->base.get_config = intel_crt_get_config;
  crt->base.get_hw_state = intel_crt_get_hw_state;
  crt->base.enable = intel_enable_crt;
 }
 connector->get_hw_state = intel_connector_get_hw_state;

 drm_connector_helper_add(&connector->base, &intel_crt_connector_helper_funcs);

 /*
 * TODO: find a proper way to discover whether we need to set the the
 * polarity and link reversal bits or not, instead of relying on the
 * BIOS.
 */
 if (HAS_PCH_LPT(display)) {
  u32 fdi_config = FDI_RX_POLARITY_REVERSED_LPT |
     FDI_RX_LINK_REVERSAL_OVERRIDE;

  display->fdi.rx_config = intel_de_read(display,
             FDI_RX_CTL(PIPE_A)) & fdi_config;
 }

 intel_crt_reset(&crt->base.base);
}