drm/crtc_helper: replace modeset fail path with something simpler

- The previous system was not very transparent, nor flexible.
- This is needed to be able to fix a few bugs in the mechanism.

Signed-off-by: Maarten Maathuis <madman2003@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index a06c5f52c289f125b1ef31b758309fb3e3455ba4..a3837b39bb8f64290ac1599c16e263fc1bbb19b8 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -704,13 +704,12 @@ EXPORT_SYMBOL(drm_crtc_helper_set_mode);
 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;
+       struct drm_crtc *save_crtcs, *new_crtc, *crtc;
+       struct drm_encoder *save_encoders, *new_encoder, *encoder;
        struct drm_framebuffer *old_fb = NULL;
-       bool save_enabled;
        bool mode_changed = false; /* if true do a full mode set */
        bool fb_changed = false; /* if true and !mode_changed just do a flip */
-       struct drm_connector *connector;
+       struct drm_connector *save_connectors, *connector;
        int count = 0, ro, fail = 0;
        struct drm_crtc_helper_funcs *crtc_funcs;
        int ret = 0;
@@ -735,25 +734,47 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 
        dev = set->crtc->dev;
 
-       /* save previous config */
-       save_enabled = set->crtc->enabled;
-
-       /*
-        * We do mode_config.num_connectors here since we'll look at the
-        * CRTC and encoder associated with each connector later.
-        */
-       save_crtcs = kzalloc(dev->mode_config.num_connector *
-                            sizeof(struct drm_crtc *), GFP_KERNEL);
+       /* Allocate space for the backup of all (non-pointer) crtc, encoder and
+        * connector data. */
+       save_crtcs = kzalloc(dev->mode_config.num_crtc *
+                            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);
+       save_encoders = kzalloc(dev->mode_config.num_encoder *
+                               sizeof(struct drm_encoder), GFP_KERNEL);
        if (!save_encoders) {
                kfree(save_crtcs);
                return -ENOMEM;
        }
 
+       save_connectors = kzalloc(dev->mode_config.num_connector *
+                               sizeof(struct drm_connector), GFP_KERNEL);
+       if (!save_connectors) {
+               kfree(save_crtcs);
+               kfree(save_encoders);
+               return -ENOMEM;
+       }
+
+       /* Copy data. Note that driver private data is not affected.
+        * Should anything bad happen only the expected state is
+        * restored, not the drivers personal bookkeeping.
+        */
+       count = 0;
+       list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+               save_crtcs[count++] = *crtc;
+       }
+
+       count = 0;
+       list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+               save_encoders[count++] = *encoder;
+       }
+
+       count = 0;
+       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+               save_connectors[count++] = *connector;
+       }
+
        /* 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) {
@@ -786,7 +807,6 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
        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) {
@@ -809,7 +829,7 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 
        if (fail) {
                ret = -EINVAL;
-               goto fail_no_encoder;
+               goto fail;
        }
 
        count = 0;
@@ -817,8 +837,6 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                if (!connector->encoder)
                        continue;
 
-               save_crtcs[count++] = connector->encoder->crtc;
-
                if (connector->encoder->crtc == set->crtc)
                        new_crtc = NULL;
                else
@@ -833,7 +851,7 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                if (new_crtc &&
                    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
                        ret = -EINVAL;
-                       goto fail_set_mode;
+                       goto fail;
                }
                if (new_crtc != connector->encoder->crtc) {
                        DRM_DEBUG_KMS("crtc changed, full mode switch\n");
@@ -862,7 +880,7 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                                DRM_ERROR("failed to set mode on crtc %p\n",
                                          set->crtc);
                                ret = -EINVAL;
-                               goto fail_set_mode;
+                               goto fail;
                        }
                        /* TODO are these needed? */
                        set->crtc->desired_x = set->x;
@@ -877,30 +895,34 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                ret = crtc_funcs->mode_set_base(set->crtc,
                                                set->x, set->y, old_fb);
                if (ret != 0)
-                   goto fail_set_mode;
+                       goto fail;
        }
 
+       kfree(save_connectors);
        kfree(save_encoders);
        kfree(save_crtcs);
        return 0;
 
-fail_set_mode:
-       set->crtc->enabled = save_enabled;
-       set->crtc->fb = old_fb;
+fail:
+       /* Restore all previous data. */
        count = 0;
-       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
-               if (!connector->encoder)
-                       continue;
+       list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+               *crtc = save_crtcs[count++];
+       }
 
-               connector->encoder->crtc = save_crtcs[count++];
+       count = 0;
+       list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+               *encoder = save_encoders[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++];
+               *connector = save_connectors[count++];
        }
+
+       kfree(save_connectors);
        kfree(save_encoders);
+       kfree(save_crtcs);
        return ret;
 }
 EXPORT_SYMBOL(drm_crtc_helper_set_config);