drm/radeon/kms: reduce probe latency on digital connectors
On a system with one HDMI and one VGA connector the latter
causes output polling to run every ten seconds. This causes
full EDID re-fetch on every poll and approx. 100ms rendering
stalls are experienced by full screen page-flipping applications.
Optimisation is to trust HPD sense on R600+ ASICs and to skip
doing these expensive probes unless HPD sense has changed.
Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=47007
agd5f: fix patch and message formatting.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@onelan.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index d2e6144..64774ac 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -827,6 +827,27 @@
return ret;
}
+static bool radeon_check_hpd_status_unchanged(struct drm_connector *connector)
+{
+ struct drm_device *dev = connector->dev;
+ struct radeon_device *rdev = dev->dev_private;
+ struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+ enum drm_connector_status status;
+
+ /* We only trust HPD on R600 and newer ASICS. */
+ if (rdev->family >= CHIP_R600
+ && radeon_connector->hpd.hpd != RADEON_HPD_NONE) {
+ if (radeon_hpd_sense(rdev, radeon_connector->hpd.hpd))
+ status = connector_status_connected;
+ else
+ status = connector_status_disconnected;
+ if (connector->status == status)
+ return true;
+ }
+
+ return false;
+}
+
/*
* DVI is complicated
* Do a DDC probe, if DDC probe passes, get the full EDID so
@@ -851,6 +872,9 @@
enum drm_connector_status ret = connector_status_disconnected;
bool dret = false;
+ if (!force && radeon_check_hpd_status_unchanged(connector))
+ return connector->status;
+
if (radeon_connector->ddc_bus)
dret = radeon_ddc_probe(radeon_connector);
if (dret) {
@@ -1254,6 +1278,9 @@
struct radeon_connector_atom_dig *radeon_dig_connector = radeon_connector->con_priv;
struct drm_encoder *encoder = radeon_best_single_encoder(connector);
+ if (!force && radeon_check_hpd_status_unchanged(connector))
+ return connector->status;
+
if (radeon_connector->edid) {
kfree(radeon_connector->edid);
radeon_connector->edid = NULL;