[PATCH 3/3] drm/radeon/kms: reduce probe latency on digital connectors

[alexdeuc...@gmail.com]

From: Tvrtko Ursulin 

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 
Signed-off-by: Alex Deucher 
---
 drivers/gpu/drm/radeon/radeon_connectors.c |   27 +++
 1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c 
b/drivers/gpu/drm/radeon/radeon_connectors.c
index f7d39ac..dfbd391 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -827,6 +827,27 @@ static int radeon_dvi_get_modes(struct drm_connector 
*connector)
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 @@ radeon_dvi_detect(struct drm_connector *connector, bool 
force)
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) {
@@ -1245,6 +1269,9 @@ radeon_dp_detect(struct drm_connector *connector, bool 
force)
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;
-- 
1.7.7.5

[PATCH 3/3] drm/radeon/kms: reduce probe latency on digital connectors

[alexdeucher]

From: Tvrtko Ursulin tvrtko.ursu...@onelan.co.uk

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.ursu...@onelan.co.uk
Signed-off-by: Alex Deucher alexander.deuc...@amd.com
---
 drivers/gpu/drm/radeon/radeon_connectors.c |   27 +++
 1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c 
b/drivers/gpu/drm/radeon/radeon_connectors.c
index f7d39ac..dfbd391 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -827,6 +827,27 @@ static int radeon_dvi_get_modes(struct drm_connector 
*connector)
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 @@ radeon_dvi_detect(struct drm_connector *connector, bool 
force)
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) {
@@ -1245,6 +1269,9 @@ radeon_dp_detect(struct drm_connector *connector, bool 
force)
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;
-- 
1.7.7.5

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