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authorMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2017-04-06 20:55:20 +0200
committerMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2017-04-06 21:29:23 +0200
commit6c5ed5ae353cdf156f9ac4db17e15db56b4de880 (patch)
treed24402c7bef516de0f3ec69318606b67065954cb /drivers/gpu/drm/drm_probe_helper.c
parent99748ab64fcc857837acfd754b530487a490edb5 (diff)
drm/atomic: Acquire connection_mutex lock in drm_helper_probe_single_connector_modes, v4.
mode_valid() called from drm_helper_probe_single_connector_modes() may need to look at connector->state because what a valid mode is may depend on connector properties being set. For example some HDMI modes might be rejected when a connector property forces the connector into DVI mode. Some implementations of detect() already lock all state, so we have to pass an acquire_ctx to them to prevent a deadlock. This means changing the function signature of detect() slightly, and passing the acquire_ctx for locking multiple crtc's. For the callbacks, it will always be non-zero. To allow callers not to worry about this, drm_helper_probe_detect_ctx is added which might handle -EDEADLK for you. Changes since v1: - Always set ctx parameter. Changes since v2: - Always take connection_mutex when probing. Changes since v3: - Remove the ctx from intel_dp_long_pulse, and add WARN_ON(!connection_mutex) (danvet) - Update docs to clarify the locking situation. (danvet) Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Boris Brezillon <boris.brezillon@free-electrons.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1491504920-4017-1-git-send-email-maarten.lankhorst@linux.intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_probe_helper.c')
-rw-r--r--drivers/gpu/drm/drm_probe_helper.c100
1 files changed, 92 insertions, 8 deletions
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index efb5e5e8ce62..1b0c14ab3fff 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -169,12 +169,73 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
EXPORT_SYMBOL(drm_kms_helper_poll_enable);
static enum drm_connector_status
-drm_connector_detect(struct drm_connector *connector, bool force)
+drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
{
- return connector->funcs->detect ?
- connector->funcs->detect(connector, force) :
- connector_status_connected;
+ const struct drm_connector_helper_funcs *funcs = connector->helper_private;
+ struct drm_modeset_acquire_ctx ctx;
+ int ret;
+
+ drm_modeset_acquire_init(&ctx, 0);
+
+retry:
+ ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
+ if (!ret) {
+ if (funcs->detect_ctx)
+ ret = funcs->detect_ctx(connector, &ctx, force);
+ else if (connector->funcs->detect)
+ ret = connector->funcs->detect(connector, force);
+ else
+ ret = connector_status_connected;
+ }
+
+ if (ret == -EDEADLK) {
+ drm_modeset_backoff(&ctx);
+ goto retry;
+ }
+
+ if (WARN_ON(ret < 0))
+ ret = connector_status_unknown;
+
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+
+ return ret;
+}
+
+/**
+ * drm_helper_probe_detect - probe connector status
+ * @connector: connector to probe
+ * @ctx: acquire_ctx, or NULL to let this function handle locking.
+ * @force: Whether destructive probe operations should be performed.
+ *
+ * This function calls the detect callbacks of the connector.
+ * This function returns &drm_connector_status, or
+ * if @ctx is set, it might also return -EDEADLK.
+ */
+int
+drm_helper_probe_detect(struct drm_connector *connector,
+ struct drm_modeset_acquire_ctx *ctx,
+ bool force)
+{
+ const struct drm_connector_helper_funcs *funcs = connector->helper_private;
+ struct drm_device *dev = connector->dev;
+ int ret;
+
+ if (!ctx)
+ return drm_helper_probe_detect_ctx(connector, force);
+
+ ret = drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
+ if (ret)
+ return ret;
+
+ if (funcs->detect_ctx)
+ return funcs->detect_ctx(connector, ctx, force);
+ else if (connector->funcs->detect)
+ return connector->funcs->detect(connector, force);
+ else
+ return connector_status_connected;
}
+EXPORT_SYMBOL(drm_helper_probe_detect);
/**
* drm_helper_probe_single_connector_modes - get complete set of display modes
@@ -239,15 +300,27 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
struct drm_display_mode *mode;
const struct drm_connector_helper_funcs *connector_funcs =
connector->helper_private;
- int count = 0;
+ int count = 0, ret;
int mode_flags = 0;
bool verbose_prune = true;
enum drm_connector_status old_status;
+ struct drm_modeset_acquire_ctx ctx;
WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+ drm_modeset_acquire_init(&ctx, 0);
+
DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
connector->name);
+
+retry:
+ ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
+ if (ret == -EDEADLK) {
+ drm_modeset_backoff(&ctx);
+ goto retry;
+ } else
+ WARN_ON(ret < 0);
+
/* set all old modes to the stale state */
list_for_each_entry(mode, &connector->modes, head)
mode->status = MODE_STALE;
@@ -263,7 +336,15 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
if (connector->funcs->force)
connector->funcs->force(connector);
} else {
- connector->status = drm_connector_detect(connector, true);
+ ret = drm_helper_probe_detect(connector, &ctx, true);
+
+ if (ret == -EDEADLK) {
+ drm_modeset_backoff(&ctx);
+ goto retry;
+ } else if (WARN(ret < 0, "Invalid return value %i for connector detection\n", ret))
+ ret = connector_status_unknown;
+
+ connector->status = ret;
}
/*
@@ -355,6 +436,9 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
prune:
drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+
if (list_empty(&connector->modes))
return 0;
@@ -440,7 +524,7 @@ static void output_poll_execute(struct work_struct *work)
repoll = true;
- connector->status = drm_connector_detect(connector, false);
+ connector->status = drm_helper_probe_detect(connector, NULL, false);
if (old_status != connector->status) {
const char *old, *new;
@@ -588,7 +672,7 @@ bool drm_helper_hpd_irq_event(struct drm_device *dev)
old_status = connector->status;
- connector->status = drm_connector_detect(connector, false);
+ connector->status = drm_helper_probe_detect(connector, NULL, false);
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
connector->base.id,
connector->name,