Quelle  intel_load_detect.c   Sprache: C

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2023 Intel Corporation
 */

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_atomic_uapi.h>
#include <drm/drm_print.h>

#include "intel_atomic.h"
#include "intel_crtc.h"
#include "intel_display_core.h"
#include "intel_display_types.h"
#include "intel_load_detect.h"

/* VESA 640x480x72Hz mode to set on the pipe */
static const struct drm_display_mode load_detect_mode = {
 DRM_MODE("640x480", DRM_MODE_TYPE_DEFAULT, 31500, 640, 664,
   704, 832, 0, 480, 489, 491, 520, 0, DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
};

static int intel_modeset_disable_planes(struct drm_atomic_state *state,
     struct drm_crtc *crtc)
{
 struct drm_plane *plane;
 struct drm_plane_state *plane_state;
 int ret, i;

 ret = drm_atomic_add_affected_planes(state, crtc);
 if (ret)
  return ret;

 for_each_new_plane_in_state(state, plane, plane_state, i) {
  if (plane_state->crtc != crtc)
   continue;

  ret = drm_atomic_set_crtc_for_plane(plane_state, NULL);
  if (ret)
   return ret;

  drm_atomic_set_fb_for_plane(plane_state, NULL);
 }

 return 0;
}

struct drm_atomic_state *
intel_load_detect_get_pipe(struct drm_connector *connector,
      struct drm_modeset_acquire_ctx *ctx)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_encoder *encoder =
  intel_attached_encoder(to_intel_connector(connector));
 struct intel_crtc *possible_crtc;
 struct intel_crtc *crtc = NULL;
 struct drm_mode_config *config = &display->drm->mode_config;
 struct drm_atomic_state *state = NULL, *restore_state = NULL;
 struct drm_connector_state *connector_state;
 struct intel_crtc_state *crtc_state;
 int ret;

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

 drm_WARN_ON(display->drm, !drm_modeset_is_locked(&config->connection_mutex));

 /*
 * Algorithm gets a little messy:
 *
 *   - if the connector already has an assigned crtc, use it (but make
 *     sure it's on first)
 *
 *   - try to find the first unused crtc that can drive this connector,
 *     and use that if we find one
 */

 /* See if we already have a CRTC for this connector */
 if (connector->state->crtc) {
  crtc = to_intel_crtc(connector->state->crtc);

  ret = drm_modeset_lock(&crtc->base.mutex, ctx);
  if (ret)
   goto fail;

  /* Make sure the crtc and connector are running */
  goto found;
 }

 /* Find an unused one (if possible) */
 for_each_intel_crtc(display->drm, possible_crtc) {
  if (!(encoder->base.possible_crtcs &
        drm_crtc_mask(&possible_crtc->base)))
   continue;

  ret = drm_modeset_lock(&possible_crtc->base.mutex, ctx);
  if (ret)
   goto fail;

  if (possible_crtc->base.state->enable) {
   drm_modeset_unlock(&possible_crtc->base.mutex);
   continue;
  }

  crtc = possible_crtc;
  break;
 }

 /*
 * If we didn't find an unused CRTC, don't use any.
 */
 if (!crtc) {
  drm_dbg_kms(display->drm,
       "no pipe available for load-detect\n");
  ret = -ENODEV;
  goto fail;
 }

found:
 state = drm_atomic_state_alloc(display->drm);
 restore_state = drm_atomic_state_alloc(display->drm);
 if (!state || !restore_state) {
  ret = -ENOMEM;
  goto fail;
 }

 state->acquire_ctx = ctx;
 to_intel_atomic_state(state)->internal = true;

 restore_state->acquire_ctx = ctx;
 to_intel_atomic_state(restore_state)->internal = true;

 connector_state = drm_atomic_get_connector_state(state, connector);
 if (IS_ERR(connector_state)) {
  ret = PTR_ERR(connector_state);
  goto fail;
 }

 ret = drm_atomic_set_crtc_for_connector(connector_state, &crtc->base);
 if (ret)
  goto fail;

 crtc_state = intel_atomic_get_crtc_state(state, crtc);
 if (IS_ERR(crtc_state)) {
  ret = PTR_ERR(crtc_state);
  goto fail;
 }

 crtc_state->uapi.active = true;

 ret = drm_atomic_set_mode_for_crtc(&crtc_state->uapi,
        &load_detect_mode);
 if (ret)
  goto fail;

 ret = intel_modeset_disable_planes(state, &crtc->base);
 if (ret)
  goto fail;

 ret = PTR_ERR_OR_ZERO(drm_atomic_get_connector_state(restore_state, connector));
 if (!ret)
  ret = PTR_ERR_OR_ZERO(drm_atomic_get_crtc_state(restore_state, &crtc->base));
 if (!ret)
  ret = drm_atomic_add_affected_planes(restore_state, &crtc->base);
 if (ret) {
  drm_dbg_kms(display->drm,
       "Failed to create a copy of old state to restore: %i\n",
       ret);
  goto fail;
 }

 ret = drm_atomic_commit(state);
 if (ret) {
  drm_dbg_kms(display->drm,
       "failed to set mode on load-detect pipe\n");
  goto fail;
 }

 drm_atomic_state_put(state);

 /* let the connector get through one full cycle before testing */
 intel_crtc_wait_for_next_vblank(crtc);

 return restore_state;

fail:
 if (state) {
  drm_atomic_state_put(state);
  state = NULL;
 }
 if (restore_state) {
  drm_atomic_state_put(restore_state);
  restore_state = NULL;
 }

 if (ret == -EDEADLK)
  return ERR_PTR(ret);

 return NULL;
}

void intel_load_detect_release_pipe(struct drm_connector *connector,
        struct drm_atomic_state *state,
        struct drm_modeset_acquire_ctx *ctx)
{
 struct intel_display *display = to_intel_display(connector->dev);
 struct intel_encoder *intel_encoder =
  intel_attached_encoder(to_intel_connector(connector));
 struct drm_encoder *encoder = &intel_encoder->base;
 int ret;

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

 if (IS_ERR_OR_NULL(state))
  return;

 ret = drm_atomic_helper_commit_duplicated_state(state, ctx);
 if (ret)
  drm_dbg_kms(display->drm,
       "Couldn't release load detect pipe: %i\n", ret);
 drm_atomic_state_put(state);
}