From: Sean Paul <seanpaul@xxxxxxxxxxxx>
This reverts commit 8d813d1a535c8c7503a5f4061654a73026be8c5e.
This patchset breaks on intel platforms and was previously NACK'd by
Ville.
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Fernando Ramos <greenfoo@xxxxxx>
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
---
drivers/gpu/drm/drm_modeset_lock.c | 94 +++++++++++++++++++++++++++++-
include/drm/drm_modeset_lock.h | 2 +
2 files changed, 93 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c
index afd1351749a5..fcfe1a03c4a1 100644
--- a/drivers/gpu/drm/drm_modeset_lock.c
+++ b/drivers/gpu/drm/drm_modeset_lock.c
@@ -77,6 +77,93 @@
static DEFINE_WW_CLASS(crtc_ww_class);
+/**
+ * drm_modeset_lock_all - take all modeset locks
+ * @dev: DRM device
+ *
+ * This function takes all modeset locks, suitable where a more fine-grained
+ * scheme isn't (yet) implemented. Locks must be dropped by calling the
+ * drm_modeset_unlock_all() function.
+ *
+ * This function is deprecated. It allocates a lock acquisition context and
+ * stores it in &drm_device.mode_config. This facilitate conversion of
+ * existing code because it removes the need to manually deal with the
+ * acquisition context, but it is also brittle because the context is global
+ * and care must be taken not to nest calls. New code should use the
+ * drm_modeset_lock_all_ctx() function and pass in the context explicitly.
+ */
+void drm_modeset_lock_all(struct drm_device *dev)
+{
+ struct drm_mode_config *config = &dev->mode_config;
+ struct drm_modeset_acquire_ctx *ctx;
+ int ret;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL);
+ if (WARN_ON(!ctx))
+ return;
+
+ mutex_lock(&config->mutex);
+
+ drm_modeset_acquire_init(ctx, 0);
+
+retry:
+ ret = drm_modeset_lock_all_ctx(dev, ctx);
+ if (ret < 0) {
+ if (ret == -EDEADLK) {
+ drm_modeset_backoff(ctx);
+ goto retry;
+ }
+
+ drm_modeset_acquire_fini(ctx);
+ kfree(ctx);
+ return;
+ }
+ ww_acquire_done(&ctx->ww_ctx);
+
+ WARN_ON(config->acquire_ctx);
+
+ /*
+ * We hold the locks now, so it is safe to stash the acquisition
+ * context for drm_modeset_unlock_all().
+ */
+ config->acquire_ctx = ctx;
+
+ drm_warn_on_modeset_not_all_locked(dev);
+}
+EXPORT_SYMBOL(drm_modeset_lock_all);
+
+/**
+ * drm_modeset_unlock_all - drop all modeset locks
+ * @dev: DRM device
+ *
+ * This function drops all modeset locks taken by a previous call to the
+ * drm_modeset_lock_all() function.
+ *
+ * This function is deprecated. It uses the lock acquisition context stored
+ * in &drm_device.mode_config. This facilitates conversion of existing
+ * code because it removes the need to manually deal with the acquisition
+ * context, but it is also brittle because the context is global and care must
+ * be taken not to nest calls. New code should pass the acquisition context
+ * directly to the drm_modeset_drop_locks() function.
+ */
+void drm_modeset_unlock_all(struct drm_device *dev)
+{
+ struct drm_mode_config *config = &dev->mode_config;
+ struct drm_modeset_acquire_ctx *ctx = config->acquire_ctx;
+
+ if (WARN_ON(!ctx))
+ return;
+
+ config->acquire_ctx = NULL;
+ drm_modeset_drop_locks(ctx);
+ drm_modeset_acquire_fini(ctx);
+
+ kfree(ctx);
+
+ mutex_unlock(&dev->mode_config.mutex);
+}
+EXPORT_SYMBOL(drm_modeset_unlock_all);
+
/**
* drm_warn_on_modeset_not_all_locked - check that all modeset locks are locked
* @dev: device
@@ -293,9 +380,10 @@ EXPORT_SYMBOL(drm_modeset_unlock);
* This function takes all modeset locks, suitable where a more fine-grained
* scheme isn't (yet) implemented.
*
- * It doesn't take the &drm_mode_config.mutex since that lock isn't required for
- * modeset state changes. Callers which need to grab that lock too need to do so
- * outside of the acquire context @ctx.
+ * Unlike drm_modeset_lock_all(), it doesn't take the &drm_mode_config.mutex
+ * since that lock isn't required for modeset state changes. Callers which
+ * need to grab that lock too need to do so outside of the acquire context
+ * @ctx.
*
* Locks acquired with this function should be released by calling the
* drm_modeset_drop_locks() function on @ctx.
diff --git a/include/drm/drm_modeset_lock.h b/include/drm/drm_modeset_lock.h
index 865e64bcc4cb..aafd07388eb7 100644
--- a/include/drm/drm_modeset_lock.h
+++ b/include/drm/drm_modeset_lock.h
@@ -132,6 +132,8 @@ struct drm_device;
struct drm_crtc;
struct drm_plane;
+void drm_modeset_lock_all(struct drm_device *dev);
+void drm_modeset_unlock_all(struct drm_device *dev);
void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
int drm_modeset_lock_all_ctx(struct drm_device *dev,
--
Sean Paul, Software Engineer, Google / Chromium OS
