UPSTREAM: drm/atomic-helper: Implement subsystem-level suspend/resume

Provide subsystem-level suspend and resume helpers that can be used to
implement suspend/resume on atomic mode-setting enabled drivers.

v2: simplify locking, enhance kerneldoc comments
v3: pass lock acquisition context by parameter, improve kerneldoc
v4: - remove redundant code (already provided by atomic helpers)
      (Maarten Lankhorst)
    - move backoff dance from drm_modeset_lock_all_ctx() into suspend
      helper (Daniel Vetter)
v5: handle potential EDEADLK from drm_atomic_helper_duplicate_state()
    and drm_atomic_helper_disable_all() (Daniel Vetter)

Change-Id: I58c5b794cdafa6c9f2594376fc2e98918156e409
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449075005-13937-2-git-send-email-thierry.reding@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
(cherry picked from 1494276000db789c6d2acd85747be4707051c801)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index f8b1e8ea2a2cbc200c59a1935ad30390bb6ec9ba..bdcf366edb6f528bc96e45fe3bc998be0cbe2d8c 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1833,6 +1833,161 @@ commit:
        return 0;
 }
 
+/**
+ * drm_atomic_helper_disable_all - disable all currently active outputs
+ * @dev: DRM device
+ * @ctx: lock acquisition context
+ *
+ * Loops through all connectors, finding those that aren't turned off and then
+ * turns them off by setting their DPMS mode to OFF and deactivating the CRTC
+ * that they are connected to.
+ *
+ * This is used for example in suspend/resume to disable all currently active
+ * functions when suspending.
+ *
+ * Note that if callers haven't already acquired all modeset locks this might
+ * return -EDEADLK, which must be handled by calling drm_modeset_backoff().
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ *
+ * See also:
+ * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
+ */
+int drm_atomic_helper_disable_all(struct drm_device *dev,
+                                 struct drm_modeset_acquire_ctx *ctx)
+{
+       struct drm_atomic_state *state;
+       struct drm_connector *conn;
+       int err;
+
+       state = drm_atomic_state_alloc(dev);
+       if (!state)
+               return -ENOMEM;
+
+       state->acquire_ctx = ctx;
+
+       drm_for_each_connector(conn, dev) {
+               struct drm_crtc *crtc = conn->state->crtc;
+               struct drm_crtc_state *crtc_state;
+
+               if (!crtc || conn->dpms != DRM_MODE_DPMS_ON)
+                       continue;
+
+               crtc_state = drm_atomic_get_crtc_state(state, crtc);
+               if (IS_ERR(crtc_state)) {
+                       err = PTR_ERR(crtc_state);
+                       goto free;
+               }
+
+               crtc_state->active = false;
+       }
+
+       err = drm_atomic_commit(state);
+
+free:
+       if (err < 0)
+               drm_atomic_state_free(state);
+
+       return err;
+}
+EXPORT_SYMBOL(drm_atomic_helper_disable_all);
+
+/**
+ * drm_atomic_helper_suspend - subsystem-level suspend helper
+ * @dev: DRM device
+ *
+ * Duplicates the current atomic state, disables all active outputs and then
+ * returns a pointer to the original atomic state to the caller. Drivers can
+ * pass this pointer to the drm_atomic_helper_resume() helper upon resume to
+ * restore the output configuration that was active at the time the system
+ * entered suspend.
+ *
+ * Note that it is potentially unsafe to use this. The atomic state object
+ * returned by this function is assumed to be persistent. Drivers must ensure
+ * that this holds true. Before calling this function, drivers must make sure
+ * to suspend fbdev emulation so that nothing can be using the device.
+ *
+ * Returns:
+ * A pointer to a copy of the state before suspend on success or an ERR_PTR()-
+ * encoded error code on failure. Drivers should store the returned atomic
+ * state object and pass it to the drm_atomic_helper_resume() helper upon
+ * resume.
+ *
+ * See also:
+ * drm_atomic_helper_duplicate_state(), drm_atomic_helper_disable_all(),
+ * drm_atomic_helper_resume()
+ */
+struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev)
+{
+       struct drm_modeset_acquire_ctx ctx;
+       struct drm_atomic_state *state;
+       int err;
+
+       drm_modeset_acquire_init(&ctx, 0);
+
+retry:
+       err = drm_modeset_lock_all_ctx(dev, &ctx);
+       if (err < 0) {
+               state = ERR_PTR(err);
+               goto unlock;
+       }
+
+       state = drm_atomic_helper_duplicate_state(dev, &ctx);
+       if (IS_ERR(state))
+               goto unlock;
+
+       err = drm_atomic_helper_disable_all(dev, &ctx);
+       if (err < 0) {
+               drm_atomic_state_free(state);
+               state = ERR_PTR(err);
+               goto unlock;
+       }
+
+unlock:
+       if (PTR_ERR(state) == -EDEADLK) {
+               drm_modeset_backoff(&ctx);
+               goto retry;
+       }
+
+       drm_modeset_drop_locks(&ctx);
+       drm_modeset_acquire_fini(&ctx);
+       return state;
+}
+EXPORT_SYMBOL(drm_atomic_helper_suspend);
+
+/**
+ * drm_atomic_helper_resume - subsystem-level resume helper
+ * @dev: DRM device
+ * @state: atomic state to resume to
+ *
+ * Calls drm_mode_config_reset() to synchronize hardware and software states,
+ * grabs all modeset locks and commits the atomic state object. This can be
+ * used in conjunction with the drm_atomic_helper_suspend() helper to
+ * implement suspend/resume for drivers that support atomic mode-setting.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ *
+ * See also:
+ * drm_atomic_helper_suspend()
+ */
+int drm_atomic_helper_resume(struct drm_device *dev,
+                            struct drm_atomic_state *state)
+{
+       struct drm_mode_config *config = &dev->mode_config;
+       int err;
+
+       drm_mode_config_reset(dev);
+       drm_modeset_lock_all(dev);
+       state->acquire_ctx = config->acquire_ctx;
+       err = drm_atomic_commit(state);
+       drm_modeset_unlock_all(dev);
+
+       return err;
+}
+EXPORT_SYMBOL(drm_atomic_helper_resume);
+
 /**
  * drm_atomic_helper_crtc_set_property - helper for crtc properties
  * @crtc: DRM crtc
@@ -2446,7 +2601,9 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
  * @ctx: lock acquisition context
  *
  * Makes a copy of the current atomic state by looping over all objects and
- * duplicating their respective states.
+ * duplicating their respective states. This is used for example by suspend/
+ * resume support code to save the state prior to suspend such that it can
+ * be restored upon resume.
  *
  * Note that this treats atomic state as persistent between save and restore.
  * Drivers must make sure that this is possible and won't result in confusion
@@ -2458,6 +2615,9 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
  * Returns:
  * A pointer to the copy of the atomic state object on success or an
  * ERR_PTR()-encoded error code on failure.
+ *
+ * See also:
+ * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
  */
 struct drm_atomic_state *
 drm_atomic_helper_duplicate_state(struct drm_device *dev,

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index ef534758a02c6f946061107aaa0262527c8a25fb..08620a25fe06f7a70fdc93dd1036b1b6862a0864 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -855,6 +855,12 @@ EXPORT_SYMBOL(drm_helper_mode_fill_fb_struct);
  * due to slight differences in allocating shared resources when the
  * configuration is restored in a different order than when userspace set it up)
  * need to use their own restore logic.
+ *
+ * This function is deprecated. New drivers should implement atomic mode-
+ * setting and use the atomic suspend/resume helpers.
+ *
+ * See also:
+ * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
  */
 void drm_helper_resume_force_mode(struct drm_device *dev)
 {

diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 186adfbb9f2e1e05336bc65255e18ffe55e46e7d..1ebc22df9b94ee2e79bb8dbde29d5f5a4da8f1a9 100644 (file)
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -85,6 +85,12 @@ int drm_atomic_helper_set_config(struct drm_mode_set *set);
 int __drm_atomic_helper_set_config(struct drm_mode_set *set,
                struct drm_atomic_state *state);
 
+int drm_atomic_helper_disable_all(struct drm_device *dev,
+                                 struct drm_modeset_acquire_ctx *ctx);
+struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev);
+int drm_atomic_helper_resume(struct drm_device *dev,
+                            struct drm_atomic_state *state);
+
 int drm_atomic_helper_crtc_set_property(struct drm_crtc *crtc,
                                        struct drm_property *property,
                                        uint64_t val);