drm: Use a nondestructive mode for output detect when polling
Destructive load-detection is very expensive and due to failings
elsewhere can trigger system wide stalls of up to 600ms. A simple
first step to correcting this is not to invoke such an expensive
and destructive load-detection operation automatically.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29536
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16265
Reported-by: Bruno Prémont <bonbons@linux-vserver.org>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index c671f60..d20b550 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1341,7 +1341,8 @@
* we have a pipe programmed in order to probe the TV.
*/
static enum drm_connector_status
-intel_tv_detect(struct drm_connector *connector)
+intel_tv_detect(struct drm_connector *connector,
+ bool nondestructive)
{
struct drm_display_mode mode;
struct drm_encoder *encoder = intel_attached_encoder(connector);
@@ -1353,7 +1354,7 @@
if (encoder->crtc && encoder->crtc->enabled) {
type = intel_tv_detect_type(intel_tv);
- } else {
+ } else if (nondestructive) {
struct drm_crtc *crtc;
int dpms_mode;
@@ -1364,10 +1365,9 @@
intel_release_load_detect_pipe(&intel_tv->base, connector,
dpms_mode);
} else
- type = -1;
- }
-
- intel_tv->type = type;
+ return connector_status_unknown;
+ } else
+ return connector->status;
if (type < 0)
return connector_status_disconnected;