DRM: add mode setting support

Add mode setting support to the DRM layer.

This is a fairly big chunk of work that allows DRM drivers to provide
full output control and configuration capabilities to userspace.  It was
motivated by several factors:
  - the fb layer's APIs aren't suited for anything but simple
    configurations
  - coordination between the fb layer, DRM layer, and various userspace
    drivers is poor to non-existent (radeonfb excepted)
  - user level mode setting drivers makes displaying panic & oops
    messages more difficult
  - suspend/resume of graphics state is possible in many more
    configurations with kernel level support

This commit just adds the core DRM part of the mode setting APIs.
Driver specific commits using these new structure and APIs will follow.

Co-authors: Jesse Barnes <jbarnes@virtuousgeek.org>, Jakob Bornecrantz <jakob@tungstengraphics.com>
Contributors: Alan Hourihane <alanh@tungstengraphics.com>, Maarten Maathuis <madman2003@gmail.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 822 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
new file mode 100644
index 000000000000..887ed33b0694
--- /dev/null
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -0,0 +1,822 @@
+/*
+ * Copyright (c) 2006-2008 Intel Corporation
+ * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
+ *
+ * DRM core CRTC related functions
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ *
+ * Authors:
+ *      Keith Packard
+ *      Eric Anholt <eric@anholt.net>
+ *      Dave Airlie <airlied@linux.ie>
+ *      Jesse Barnes <jesse.barnes@intel.com>
+ */
+
+#include "drmP.h"
+#include "drm_crtc.h"
+#include "drm_crtc_helper.h"
+
+/*
+ * Detailed mode info for a standard 640x480@60Hz monitor
+ */
+static struct drm_display_mode std_mode[] = {
+        { DRM_MODE("640x480", DRM_MODE_TYPE_DEFAULT, 25200, 640, 656,
+                   752, 800, 0, 480, 490, 492, 525, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) },
+};
+
+/**
+ * drm_helper_probe_connector_modes - get complete set of display modes
+ * @dev: DRM device
+ * @maxX: max width for modes
+ * @maxY: max height for modes
+ *
+ * LOCKING:
+ * Caller must hold mode config lock.
+ *
+ * Based on @dev's mode_config layout, scan all the connectors and try to detect
+ * modes on them.  Modes will first be added to the connector's probed_modes
+ * list, then culled (based on validity and the @maxX, @maxY parameters) and
+ * put into the normal modes list.
+ *
+ * Intended to be used either at bootup time or when major configuration
+ * changes have occurred.
+ *
+ * FIXME: take into account monitor limits
+ */
+void drm_helper_probe_single_connector_modes(struct drm_connector *connector,
+                                             uint32_t maxX, uint32_t maxY)
+{
+        struct drm_device *dev = connector->dev;
+        struct drm_display_mode *mode, *t;
+        struct drm_connector_helper_funcs *connector_funcs =
+                connector->helper_private;
+        int ret;
+
+        DRM_DEBUG("%s\n", drm_get_connector_name(connector));
+        /* set all modes to the unverified state */
+        list_for_each_entry_safe(mode, t, &connector->modes, head)
+                mode->status = MODE_UNVERIFIED;
+
+        connector->status = connector->funcs->detect(connector);
+
+        if (connector->status == connector_status_disconnected) {
+                DRM_DEBUG("%s is disconnected\n",
+                          drm_get_connector_name(connector));
+                /* TODO set EDID to NULL */
+                return;
+        }
+
+        ret = (*connector_funcs->get_modes)(connector);
+
+        if (ret) {
+                drm_mode_connector_list_update(connector);
+        }
+
+        if (maxX && maxY)
+                drm_mode_validate_size(dev, &connector->modes, maxX,
+                                       maxY, 0);
+        list_for_each_entry_safe(mode, t, &connector->modes, head) {
+                if (mode->status == MODE_OK)
+                        mode->status = connector_funcs->mode_valid(connector,
+                                                                   mode);
+        }
+
+
+        drm_mode_prune_invalid(dev, &connector->modes, true);
+
+        if (list_empty(&connector->modes)) {
+                struct drm_display_mode *stdmode;
+
+                DRM_DEBUG("No valid modes on %s\n",
+                          drm_get_connector_name(connector));
+
+                /* Should we do this here ???
+                 * When no valid EDID modes are available we end up
+                 * here and bailed in the past, now we add a standard
+                 * 640x480@60Hz mode and carry on.
+                 */
+                stdmode = drm_mode_duplicate(dev, &std_mode[0]);
+                drm_mode_probed_add(connector, stdmode);
+                drm_mode_list_concat(&connector->probed_modes,
+                                     &connector->modes);
+
+                DRM_DEBUG("Adding standard 640x480 @ 60Hz to %s\n",
+                          drm_get_connector_name(connector));
+        }
+
+        drm_mode_sort(&connector->modes);
+
+        DRM_DEBUG("Probed modes for %s\n", drm_get_connector_name(connector));
+        list_for_each_entry_safe(mode, t, &connector->modes, head) {
+                mode->vrefresh = drm_mode_vrefresh(mode);
+
+                drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
+                drm_mode_debug_printmodeline(mode);
+        }
+}
+EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
+
+void drm_helper_probe_connector_modes(struct drm_device *dev, uint32_t maxX,
+                                      uint32_t maxY)
+{
+        struct drm_connector *connector;
+
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                drm_helper_probe_single_connector_modes(connector, maxX, maxY);
+        }
+}
+EXPORT_SYMBOL(drm_helper_probe_connector_modes);
+
+
+/**
+ * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
+ * @crtc: CRTC to check
+ *
+ * LOCKING:
+ * Caller must hold mode config lock.
+ *
+ * Walk @crtc's DRM device's mode_config and see if it's in use.
+ *
+ * RETURNS:
+ * True if @crtc is part of the mode_config, false otherwise.
+ */
+bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
+{
+        struct drm_encoder *encoder;
+        struct drm_device *dev = crtc->dev;
+        /* FIXME: Locking around list access? */
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head)
+                if (encoder->crtc == crtc)
+                        return true;
+        return false;
+}
+EXPORT_SYMBOL(drm_helper_crtc_in_use);
+
+/**
+ * drm_disable_unused_functions - disable unused objects
+ * @dev: DRM device
+ *
+ * LOCKING:
+ * Caller must hold mode config lock.
+ *
+ * If an connector or CRTC isn't part of @dev's mode_config, it can be disabled
+ * by calling its dpms function, which should power it off.
+ */
+void drm_helper_disable_unused_functions(struct drm_device *dev)
+{
+        struct drm_encoder *encoder;
+        struct drm_encoder_helper_funcs *encoder_funcs;
+        struct drm_crtc *crtc;
+
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+                encoder_funcs = encoder->helper_private;
+                if (!encoder->crtc)
+                        (*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
+        }
+
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+                crtc->enabled = drm_helper_crtc_in_use(crtc);
+                if (!crtc->enabled) {
+                        crtc_funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
+                        crtc->fb = NULL;
+                }
+        }
+}
+EXPORT_SYMBOL(drm_helper_disable_unused_functions);
+
+static struct drm_display_mode *drm_has_preferred_mode(struct drm_connector *connector, int width, int height)
+{
+        struct drm_display_mode *mode;
+
+        list_for_each_entry(mode, &connector->modes, head) {
+                if (drm_mode_width(mode) > width ||
+                    drm_mode_height(mode) > height)
+                        continue;
+                if (mode->type & DRM_MODE_TYPE_PREFERRED)
+                        return mode;
+        }
+        return NULL;
+}
+
+static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
+{
+        bool enable;
+
+        if (strict) {
+                enable = connector->status == connector_status_connected;
+        } else {
+                enable = connector->status != connector_status_disconnected;
+        }
+        return enable;
+}
+
+static void drm_enable_connectors(struct drm_device *dev, bool *enabled)
+{
+        bool any_enabled = false;
+        struct drm_connector *connector;
+        int i = 0;
+
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                enabled[i] = drm_connector_enabled(connector, true);
+                any_enabled |= enabled[i];
+                i++;
+        }
+
+        if (any_enabled)
+                return;
+
+        i = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                enabled[i] = drm_connector_enabled(connector, false);
+                i++;
+        }
+}
+
+static bool drm_target_preferred(struct drm_device *dev,
+                                 struct drm_display_mode **modes,
+                                 bool *enabled, int width, int height)
+{
+        struct drm_connector *connector;
+        int i = 0;
+
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+
+                if (enabled[i] == false) {
+                        i++;
+                        continue;
+                }
+
+                modes[i] = drm_has_preferred_mode(connector, width, height);
+                if (!modes[i]) {
+                        list_for_each_entry(modes[i], &connector->modes, head)
+                                break;
+                }
+                i++;
+        }
+        return true;
+}
+
+static int drm_pick_crtcs(struct drm_device *dev,
+                          struct drm_crtc **best_crtcs,
+                          struct drm_display_mode **modes,
+                          int n, int width, int height)
+{
+        int c, o;
+        struct drm_connector *connector;
+        struct drm_connector_helper_funcs *connector_funcs;
+        struct drm_encoder *encoder;
+        struct drm_crtc *best_crtc;
+        int my_score, best_score, score;
+        struct drm_crtc **crtcs, *crtc;
+
+        if (n == dev->mode_config.num_connector)
+                return 0;
+        c = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                if (c == n)
+                        break;
+                c++;
+        }
+
+        best_crtcs[n] = NULL;
+        best_crtc = NULL;
+        best_score = drm_pick_crtcs(dev, best_crtcs, modes, n+1, width, height);
+        if (modes[n] == NULL)
+                return best_score;
+
+        crtcs = kmalloc(dev->mode_config.num_connector *
+                        sizeof(struct drm_crtc *), GFP_KERNEL);
+        if (!crtcs)
+                return best_score;
+
+        my_score = 1;
+        if (connector->status == connector_status_connected)
+                my_score++;
+        if (drm_has_preferred_mode(connector, width, height))
+                my_score++;
+
+        connector_funcs = connector->helper_private;
+        encoder = connector_funcs->best_encoder(connector);
+        if (!encoder)
+                goto out;
+
+        connector->encoder = encoder;
+
+        /* select a crtc for this connector and then attempt to configure
+           remaining connectors */
+        c = 0;
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+
+                if ((connector->encoder->possible_crtcs & (1 << c)) == 0) {
+                        c++;
+                        continue;
+                }
+
+                for (o = 0; o < n; o++)
+                        if (best_crtcs[o] == crtc)
+                                break;
+
+                if (o < n) {
+                        /* ignore cloning for now */
+                        c++;
+                        continue;
+                }
+
+                crtcs[n] = crtc;
+                memcpy(crtcs, best_crtcs, n * sizeof(struct drm_crtc *));
+                score = my_score + drm_pick_crtcs(dev, crtcs, modes, n + 1,
+                                                  width, height);
+                if (score > best_score) {
+                        best_crtc = crtc;
+                        best_score = score;
+                        memcpy(best_crtcs, crtcs,
+                               dev->mode_config.num_connector *
+                               sizeof(struct drm_crtc *));
+                }
+                c++;
+        }
+out:
+        kfree(crtcs);
+        return best_score;
+}
+
+static void drm_setup_crtcs(struct drm_device *dev)
+{
+        struct drm_crtc **crtcs;
+        struct drm_display_mode **modes;
+        struct drm_encoder *encoder;
+        struct drm_connector *connector;
+        bool *enabled;
+        int width, height;
+        int i, ret;
+
+        width = dev->mode_config.max_width;
+        height = dev->mode_config.max_height;
+
+        /* clean out all the encoder/crtc combos */
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+                encoder->crtc = NULL;
+        }
+
+        crtcs = kcalloc(dev->mode_config.num_connector,
+                        sizeof(struct drm_crtc *), GFP_KERNEL);
+        modes = kcalloc(dev->mode_config.num_connector,
+                        sizeof(struct drm_display_mode *), GFP_KERNEL);
+        enabled = kcalloc(dev->mode_config.num_connector,
+                          sizeof(bool), GFP_KERNEL);
+
+        drm_enable_connectors(dev, enabled);
+
+        ret = drm_target_preferred(dev, modes, enabled, width, height);
+        if (!ret)
+                DRM_ERROR("Unable to find initial modes\n");
+
+        drm_pick_crtcs(dev, crtcs, modes, 0, width, height);
+
+        i = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                struct drm_display_mode *mode = modes[i];
+                struct drm_crtc *crtc = crtcs[i];
+
+                if (connector->encoder == NULL) {
+                        i++;
+                        continue;
+                }
+
+                if (mode && crtc) {
+                        crtc->desired_mode = mode;
+                        connector->encoder->crtc = crtc;
+                } else
+                        connector->encoder->crtc = NULL;
+                i++;
+        }
+
+        kfree(crtcs);
+        kfree(modes);
+        kfree(enabled);
+}
+/**
+ * drm_crtc_set_mode - set a mode
+ * @crtc: CRTC to program
+ * @mode: mode to use
+ * @x: width of mode
+ * @y: height of mode
+ *
+ * LOCKING:
+ * Caller must hold mode config lock.
+ *
+ * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
+ * to fixup or reject the mode prior to trying to set it.
+ *
+ * RETURNS:
+ * True if the mode was set successfully, or false otherwise.
+ */
+bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
+                              struct drm_display_mode *mode,
+                              int x, int y)
+{
+        struct drm_device *dev = crtc->dev;
+        struct drm_display_mode *adjusted_mode, saved_mode;
+        struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+        struct drm_encoder_helper_funcs *encoder_funcs;
+        int saved_x, saved_y;
+        struct drm_encoder *encoder;
+        bool ret = true;
+
+        adjusted_mode = drm_mode_duplicate(dev, mode);
+
+        crtc->enabled = drm_helper_crtc_in_use(crtc);
+
+        if (!crtc->enabled)
+                return true;
+
+        saved_mode = crtc->mode;
+        saved_x = crtc->x;
+        saved_y = crtc->y;
+
+        /* Update crtc values up front so the driver can rely on them for mode
+         * setting.
+         */
+        crtc->mode = *mode;
+        crtc->x = x;
+        crtc->y = y;
+
+        if (drm_mode_equal(&saved_mode, &crtc->mode)) {
+                if (saved_x != crtc->x || saved_y != crtc->y) {
+                        crtc_funcs->mode_set_base(crtc, crtc->x, crtc->y);
+                        goto done;
+                }
+        }
+
+        /* Pass our mode to the connectors and the CRTC to give them a chance to
+         * adjust it according to limitations or connector properties, and also
+         * a chance to reject the mode entirely.
+         */
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+
+                if (encoder->crtc != crtc)
+                        continue;
+                encoder_funcs = encoder->helper_private;
+                if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
+                                                      adjusted_mode))) {
+                        goto done;
+                }
+        }
+
+        if (!(ret = crtc_funcs->mode_fixup(crtc, mode, adjusted_mode))) {
+                goto done;
+        }
+
+        /* Prepare the encoders and CRTCs before setting the mode. */
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+
+                if (encoder->crtc != crtc)
+                        continue;
+                encoder_funcs = encoder->helper_private;
+                /* Disable the encoders as the first thing we do. */
+                encoder_funcs->prepare(encoder);
+        }
+
+        crtc_funcs->prepare(crtc);
+
+        /* Set up the DPLL and any encoders state that needs to adjust or depend
+         * on the DPLL.
+         */
+        crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y);
+
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+
+                if (encoder->crtc != crtc)
+                        continue;
+
+                DRM_INFO("%s: set mode %s %x\n", drm_get_encoder_name(encoder),
+                         mode->name, mode->base.id);
+                encoder_funcs = encoder->helper_private;
+                encoder_funcs->mode_set(encoder, mode, adjusted_mode);
+        }
+
+        /* Now enable the clocks, plane, pipe, and connectors that we set up. */
+        crtc_funcs->commit(crtc);
+
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+
+                if (encoder->crtc != crtc)
+                        continue;
+
+                encoder_funcs = encoder->helper_private;
+                encoder_funcs->commit(encoder);
+
+        }
+
+        /* XXX free adjustedmode */
+        drm_mode_destroy(dev, adjusted_mode);
+        /* FIXME: add subpixel order */
+done:
+        if (!ret) {
+                crtc->mode = saved_mode;
+                crtc->x = saved_x;
+                crtc->y = saved_y;
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(drm_crtc_helper_set_mode);
+
+
+/**
+ * drm_crtc_helper_set_config - set a new config from userspace
+ * @crtc: CRTC to setup
+ * @crtc_info: user provided configuration
+ * @new_mode: new mode to set
+ * @connector_set: set of connectors for the new config
+ * @fb: new framebuffer
+ *
+ * LOCKING:
+ * Caller must hold mode config lock.
+ *
+ * Setup a new configuration, provided by the user in @crtc_info, and enable
+ * it.
+ *
+ * RETURNS:
+ * Zero. (FIXME)
+ */
+int drm_crtc_helper_set_config(struct drm_mode_set *set)
+{
+        struct drm_device *dev;
+        struct drm_crtc **save_crtcs, *new_crtc;
+        struct drm_encoder **save_encoders, *new_encoder;
+        bool save_enabled;
+        bool changed = false;
+        bool flip_or_move = false;
+        struct drm_connector *connector;
+        int count = 0, ro, fail = 0;
+        struct drm_crtc_helper_funcs *crtc_funcs;
+        int ret = 0;
+
+        DRM_DEBUG("\n");
+
+        if (!set)
+                return -EINVAL;
+
+        if (!set->crtc)
+                return -EINVAL;
+
+        if (!set->crtc->helper_private)
+                return -EINVAL;
+
+        crtc_funcs = set->crtc->helper_private;
+
+        DRM_DEBUG("crtc: %p %d fb: %p connectors: %p num_connectors: %d (x, y) (%i, %i)\n",
+                  set->crtc, set->crtc->base.id, set->fb, set->connectors,
+                  (int)set->num_connectors, set->x, set->y);
+
+        dev = set->crtc->dev;
+
+        /* save previous config */
+        save_enabled = set->crtc->enabled;
+
+        /* this is meant to be num_connector not num_crtc */
+        save_crtcs = kzalloc(dev->mode_config.num_connector *
+                             sizeof(struct drm_crtc *), GFP_KERNEL);
+        if (!save_crtcs)
+                return -ENOMEM;
+
+        save_encoders = kzalloc(dev->mode_config.num_connector *
+                                sizeof(struct drm_encoders *), GFP_KERNEL);
+        if (!save_encoders) {
+                kfree(save_crtcs);
+                return -ENOMEM;
+        }
+
+        /* We should be able to check here if the fb has the same properties
+         * and then just flip_or_move it */
+        if (set->crtc->fb != set->fb) {
+                /* if we have no fb then its a change not a flip */
+                if (set->crtc->fb == NULL)
+                        changed = true;
+                else
+                        flip_or_move = true;
+        }
+
+        if (set->x != set->crtc->x || set->y != set->crtc->y)
+                flip_or_move = true;
+
+        if (set->mode && !drm_mode_equal(set->mode, &set->crtc->mode)) {
+                DRM_DEBUG("modes are different\n");
+                drm_mode_debug_printmodeline(&set->crtc->mode);
+                drm_mode_debug_printmodeline(set->mode);
+                changed = true;
+        }
+
+        /* a) traverse passed in connector list and get encoders for them */
+        count = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                struct drm_connector_helper_funcs *connector_funcs =
+                        connector->helper_private;
+                save_encoders[count++] = connector->encoder;
+                new_encoder = connector->encoder;
+                for (ro = 0; ro < set->num_connectors; ro++) {
+                        if (set->connectors[ro] == connector) {
+                                new_encoder = connector_funcs->best_encoder(connector);
+                                /* if we can't get an encoder for a connector
+                                   we are setting now - then fail */
+                                if (new_encoder == NULL)
+                                        /* don't break so fail path works correct */
+                                        fail = 1;
+                                break;
+                        }
+                }
+
+                if (new_encoder != connector->encoder) {
+                        changed = true;
+                        connector->encoder = new_encoder;
+                }
+        }
+
+        if (fail) {
+                ret = -EINVAL;
+                goto fail_no_encoder;
+        }
+
+        count = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                if (!connector->encoder)
+                        continue;
+
+                save_crtcs[count++] = connector->encoder->crtc;
+
+                if (connector->encoder->crtc == set->crtc)
+                        new_crtc = NULL;
+                else
+                        new_crtc = connector->encoder->crtc;
+
+                for (ro = 0; ro < set->num_connectors; ro++) {
+                        if (set->connectors[ro] == connector)
+                                new_crtc = set->crtc;
+                }
+                if (new_crtc != connector->encoder->crtc) {
+                        changed = true;
+                        connector->encoder->crtc = new_crtc;
+                }
+        }
+
+        /* mode_set_base is not a required function */
+        if (flip_or_move && !crtc_funcs->mode_set_base)
+                changed = true;
+
+        if (changed) {
+                set->crtc->fb = set->fb;
+                set->crtc->enabled = (set->mode != NULL);
+                if (set->mode != NULL) {
+                        DRM_DEBUG("attempting to set mode from userspace\n");
+                        drm_mode_debug_printmodeline(set->mode);
+                        if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
+                                                      set->x, set->y)) {
+                                ret = -EINVAL;
+                                goto fail_set_mode;
+                        }
+                        /* TODO are these needed? */
+                        set->crtc->desired_x = set->x;
+                        set->crtc->desired_y = set->y;
+                        set->crtc->desired_mode = set->mode;
+                }
+                drm_helper_disable_unused_functions(dev);
+        } else if (flip_or_move) {
+                if (set->crtc->fb != set->fb)
+                        set->crtc->fb = set->fb;
+                crtc_funcs->mode_set_base(set->crtc, set->x, set->y);
+        }
+
+        kfree(save_encoders);
+        kfree(save_crtcs);
+        return 0;
+
+fail_set_mode:
+        set->crtc->enabled = save_enabled;
+        count = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head)
+                connector->encoder->crtc = save_crtcs[count++];
+fail_no_encoder:
+        kfree(save_crtcs);
+        count = 0;
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+                connector->encoder = save_encoders[count++];
+        }
+        kfree(save_encoders);
+        return ret;
+}
+EXPORT_SYMBOL(drm_crtc_helper_set_config);
+
+bool drm_helper_plugged_event(struct drm_device *dev)
+{
+        DRM_DEBUG("\n");
+
+        drm_helper_probe_connector_modes(dev, dev->mode_config.max_width,
+                                         dev->mode_config.max_height);
+
+        drm_setup_crtcs(dev);
+
+        /* alert the driver fb layer */
+        dev->mode_config.funcs->fb_changed(dev);
+
+        /* FIXME: send hotplug event */
+        return true;
+}
+/**
+ * drm_initial_config - setup a sane initial connector configuration
+ * @dev: DRM device
+ * @can_grow: this configuration is growable
+ *
+ * LOCKING:
+ * Called at init time, must take mode config lock.
+ *
+ * Scan the CRTCs and connectors and try to put together an initial setup.
+ * At the moment, this is a cloned configuration across all heads with
+ * a new framebuffer object as the backing store.
+ *
+ * RETURNS:
+ * Zero if everything went ok, nonzero otherwise.
+ */
+bool drm_helper_initial_config(struct drm_device *dev, bool can_grow)
+{
+        int ret = false;
+
+        drm_helper_plugged_event(dev);
+        return ret;
+}
+EXPORT_SYMBOL(drm_helper_initial_config);
+
+/**
+ * drm_hotplug_stage_two
+ * @dev DRM device
+ * @connector hotpluged connector
+ *
+ * LOCKING.
+ * Caller must hold mode config lock, function might grab struct lock.
+ *
+ * Stage two of a hotplug.
+ *
+ * RETURNS:
+ * Zero on success, errno on failure.
+ */
+int drm_helper_hotplug_stage_two(struct drm_device *dev)
+{
+        dev->mode_config.hotplug_counter++;
+
+        drm_helper_plugged_event(dev);
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_helper_hotplug_stage_two);
+
+int drm_helper_mode_fill_fb_struct(struct drm_framebuffer *fb,
+                                   struct drm_mode_fb_cmd *mode_cmd)
+{
+        fb->width = mode_cmd->width;
+        fb->height = mode_cmd->height;
+        fb->pitch = mode_cmd->pitch;
+        fb->bits_per_pixel = mode_cmd->bpp;
+        fb->depth = mode_cmd->depth;
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_helper_mode_fill_fb_struct);
+
+int drm_helper_resume_force_mode(struct drm_device *dev)
+{
+        struct drm_crtc *crtc;
+        int ret;
+
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+
+                if (!crtc->enabled)
+                        continue;
+
+                ret = drm_crtc_helper_set_mode(crtc, &crtc->mode, crtc->x,
+                                               crtc->y);
+
+                if (ret == false)
+                        DRM_ERROR("failed to set mode on crtc %p\n", crtc);
+        }
+        return 0;
+}
+EXPORT_SYMBOL(drm_helper_resume_force_mode);