From: Shashank Sharma <shashank.sharma@xxxxxxxxx>
The current hdmi_detect() function is getting called from
many places, few of these are:
1. HDMI hot plug interrupt bottom half
2. get_resources() IOCTL family
3. drm_helper_probe_single_connector_modes() family
4. output_poll_execute()
5. status_show() etc...
Every time this function is called, it goes and reads HDMI EDID over
DDC channel. Ideally, reading EDID is only required when there is a
real hot plug, and then for all IOCTL and userspace detect functions
can be answered using this same EDID.
The current patch adds EDID caching for a finite duration (1 minute)
This is how it works:
1. With in this caching duration, when usespace get_resource and other
modeset_detect calls get called, we can use the cached EDID.
2. Even the get_mode function can use the cached EDID.
3. A delayed work will clear the cached EDID after the timeout.
4. If there is a real HDMI hotplug, within the caching duration, the
cached EDID is updates, and a new delayed work is scheduled.
Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_drv.h | 4 ++
drivers/gpu/drm/i915/intel_hdmi.c | 92 ++++++++++++++++++++++++++++++++++++---
2 files changed, 90 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 28d185d..185a45a 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -110,6 +110,8 @@
#define INTEL_DSI_VIDEO_MODE 0
#define INTEL_DSI_COMMAND_MODE 1
+#define INTEL_HDMI_EDID_CACHING_SEC 60
+
struct intel_framebuffer {
struct drm_framebuffer base;
struct drm_i915_gem_object *obj;
@@ -507,6 +509,8 @@ struct intel_hdmi {
enum hdmi_force_audio force_audio;
bool rgb_quant_range_selectable;
enum hdmi_picture_aspect aspect_ratio;
+ struct edid *edid;
+ struct delayed_work edid_work;
void (*write_infoframe)(struct drm_encoder *encoder,
enum hdmi_infoframe_type type,
const void *frame, ssize_t len);
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 5f47d35..8dc3970 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -962,6 +962,22 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
return true;
}
+/* Work function to invalidate EDID caching */
+static void intel_hdmi_invalidate_edid(struct work_struct *work)
+{
+ struct intel_hdmi *intel_hdmi = container_of(to_delayed_work(work),
+ struct intel_hdmi, edid_work);
+ struct drm_device *dev = intel_hdmi_to_dev(intel_hdmi);
+ struct drm_mode_config *mode_config = &dev->mode_config;
+
+ mutex_lock(&mode_config->mutex);
+ /* Checkpatch says kfree is NULL protected */
+ kfree(intel_hdmi->edid);
+ intel_hdmi->edid = NULL;
+ mutex_unlock(&mode_config->mutex);
+ DRM_DEBUG_DRIVER("cleaned up cached EDID\n");
+}
+
static enum drm_connector_status
intel_hdmi_detect(struct drm_connector *connector, bool force)
{
@@ -978,15 +994,58 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
connector->base.id, connector->name);
+ /*
+ * hdmi_detect() gets called from both get_resource()
+ * and HDMI hpd bottom half work function.
+ * Its not required to read EDID for every detect call until it's is
+ * from a hot plug. Lets cache the EDID as soon as we get
+ * a HPD, and then try to re-use this for all the non hpd detact calls
+ * coming with in a finite duration.
+ */
+ if (INTEL_INFO(dev)->gen < 6)
+ /* Do not break old platforms */
+ goto skip_optimization;
+
+ /* If call is from HPD, do check real status by reading EDID */
+ if (!force)
+ goto skip_optimization;
+
+ /* This is a non-hpd call, lets see if we can optimize this */
+ if (intel_hdmi->edid) {
+ /*
+ * So this is a non-hpd call, within the duration when
+ * EDID caching is valid. So previous status (valid)
+ * of connector is re-usable.
+ */
+ if (connector->status != connector_status_unknown) {
+ DRM_DEBUG_DRIVER("Reporting force status\n");
+ return connector->status;
+ }
+ }
+
+skip_optimization:
power_domain = intel_display_port_power_domain(intel_encoder);
intel_display_power_get(dev_priv, power_domain);
intel_hdmi->has_hdmi_sink = false;
intel_hdmi->has_audio = false;
intel_hdmi->rgb_quant_range_selectable = false;
+
+ /*
+ * You are well deserving, dear code, as you have survived
+ * all the optimizations. Now go and enjoy reading EDID
+ */
edid = drm_get_edid(connector,
- intel_gmbus_get_adapter(dev_priv,
- intel_hdmi->ddc_bus));
+ intel_gmbus_get_adapter(dev_priv,
+ intel_hdmi->ddc_bus));
+ /*
+ * Now when we have read new EDID, update cached EDID with
+ * latest (both NULL or non NULL). Cancel the delayed work
+ * which cleans up the cached EDID. Re-schedule if required.
+ */
+ kfree(intel_hdmi->edid);
+ intel_hdmi->edid = edid;
+ cancel_delayed_work_sync(&intel_hdmi->edid_work);
if (edid) {
if (edid->input & DRM_EDID_INPUT_DIGITAL) {
@@ -997,8 +1056,17 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
intel_hdmi->has_audio = drm_detect_monitor_audio(edid);
intel_hdmi->rgb_quant_range_selectable =
drm_rgb_quant_range_selectable(edid);
+ /*
+ * Allow re-use of cached EDID for 60 sec, as
+ * userspace modeset should happen within this
+ * duration, and multiple detect calls will be
+ * handled using cached EDID.
+ */
+ schedule_delayed_work(&intel_hdmi->edid_work,
+ msecs_to_jiffies(
+ INTEL_HDMI_EDID_CACHING_SEC
+ * 1000));
}
- kfree(edid);
}
if (status == connector_status_connected) {
@@ -1027,13 +1095,22 @@ static int intel_hdmi_get_modes(struct drm_connector *connector)
power_domain = intel_display_port_power_domain(intel_encoder);
intel_display_power_get(dev_priv, power_domain);
-
- ret = intel_ddc_get_modes(connector,
+ /*
+ * GEN6 and + have software support for EDID caching, so
+ * use cached_edid from detect call, if available.
+ */
+ if (intel_hdmi->edid && (INTEL_INFO(connector->dev)->gen >= 6)) {
+ ret = intel_connector_update_modes(connector,
+ intel_hdmi->edid);
+ DRM_DEBUG_DRIVER("Using cached EDID, got %d modes\n", ret);
+ } else {
+ ret = intel_ddc_get_modes(connector,
intel_gmbus_get_adapter(dev_priv,
intel_hdmi->ddc_bus));
+ DRM_DEBUG_DRIVER("Read EDID, got %d modes\n", ret);
+ }
intel_display_power_put(dev_priv, power_domain);
-
return ret;
}
@@ -1661,5 +1738,8 @@ void intel_hdmi_init(struct drm_device *dev, int hdmi_reg, enum port port)
intel_dig_port->hdmi.hdmi_reg = hdmi_reg;
intel_dig_port->dp.output_reg = 0;
+ /* Work function to invalidate cached EDID after timeout */
+ INIT_DELAYED_WORK(&(intel_dig_port->hdmi.edid_work),
+ intel_hdmi_invalidate_edid);
intel_hdmi_init_connector(intel_dig_port, intel_connector);
}
--
1.9.1
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