[PATCH hwc v2 09/18] drm_hwcomposer: Handle writeback connectors

[Alexandru Gheorghe <alexandru-cosmin.gheorghe@xxxxxxx>]

When writeback connectors are available assign them to displays, in
order to be able to use them for flattening of the current displayed
scene. The pipeline for each display will look like this:

CRTC ---- encoder ------------ display connector.
 |------- writeback enc ------ writeback connector.

However, the writeback connector will be later used/enabled only if
one of the following conditions are met:
 - Could be a clone of the display connector, as pointed by the
   possible_clones property.
 - The display_connector is disconnected, so we are safe to use it for
   flattening the scene that's already presented on another display.

Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@xxxxxxx>
---
 drmresources.cpp | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 drmresources.h   |  3 +++
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/drmresources.cpp b/drmresources.cpp
index 39f50be..fef6835 100644
--- a/drmresources.cpp
+++ b/drmresources.cpp
@@ -64,6 +64,14 @@ int DrmResources::Init(ResourceManager *resource_manager, char *path,
     return ret;
   }
 
+#ifdef DRM_CLIENT_CAP_WRITEBACK_CONNECTORS
+  ret = drmSetClientCap(fd(), DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1);
+  if (ret) {
+    ALOGI("Failed to set writeback cap %d", ret);
+    ret = 0;
+  }
+#endif
+
   drmModeResPtr res = drmModeGetResources(fd());
   if (!res) {
     ALOGE("Failed to get DrmResources resources");
@@ -169,7 +177,7 @@ int DrmResources::Init(ResourceManager *resource_manager, char *path,
       conn->set_display(0);
       displays_[0] = 0;
       found_primary = true;
-    } else {
+    } else if (conn->external()) {
       conn->set_display(display_num);
       displays_[display_num] = display_num;
       ++display_num;
@@ -230,6 +238,8 @@ int DrmResources::Init(ResourceManager *resource_manager, char *path,
   }
 
   for (auto &conn : connectors_) {
+    if (conn->writeback())
+      continue;
     ret = CreateDisplayPipe(conn.get());
     if (ret) {
       ALOGE("Failed CreateDisplayPipe %d with %d", conn->id(), ret);
@@ -245,7 +255,15 @@ bool DrmResources::HandlesDisplay(int display) const {
 
 DrmConnector *DrmResources::GetConnectorForDisplay(int display) const {
   for (auto &conn : connectors_) {
-    if (conn->display() == display)
+    if (conn->display() == display && !conn->writeback())
+      return conn.get();
+  }
+  return NULL;
+}
+
+DrmConnector *DrmResources::GetWritebackConnectorForDisplay(int display) const {
+  for (auto &conn : connectors_) {
+    if (conn->display() == display && conn->writeback())
       return conn.get();
   }
   return NULL;
@@ -280,6 +298,7 @@ int DrmResources::TryEncoderForDisplay(int display, DrmEncoder *enc) {
   DrmCrtc *crtc = enc->crtc();
   if (crtc && crtc->can_bind(display)) {
     crtc->set_display(display);
+    enc->set_display(display);
     return 0;
   }
 
@@ -306,6 +325,7 @@ int DrmResources::CreateDisplayPipe(DrmConnector *connector) {
   if (connector->encoder()) {
     int ret = TryEncoderForDisplay(display, connector->encoder());
     if (!ret) {
+      AttachWriteback(connector);
       return 0;
     } else if (ret != -EAGAIN) {
       ALOGE("Could not set mode %d/%d", display, ret);
@@ -317,6 +337,7 @@ int DrmResources::CreateDisplayPipe(DrmConnector *connector) {
     int ret = TryEncoderForDisplay(display, enc);
     if (!ret) {
       connector->set_encoder(enc);
+      AttachWriteback(connector);
       return 0;
     } else if (ret != -EAGAIN) {
       ALOGE("Could not set mode %d/%d", display, ret);
@@ -328,6 +349,43 @@ int DrmResources::CreateDisplayPipe(DrmConnector *connector) {
   return -ENODEV;
 }
 
+/*
+ * Attach writeback connector to the CRTC linked to the display_conn
+ *
+ */
+int DrmResources::AttachWriteback(DrmConnector *display_conn) {
+  int ret = -EINVAL;
+  if (display_conn->writeback())
+    return -EINVAL;
+  DrmEncoder *display_enc = display_conn->encoder();
+  if (!display_enc)
+    return -EINVAL;
+  DrmCrtc *display_crtc = display_enc->crtc();
+  if (!display_crtc)
+    return -EINVAL;
+  if (GetWritebackConnectorForDisplay(display_crtc->display()) != NULL)
+    return -EINVAL;
+  for (auto &writeback_conn : connectors_) {
+    if (writeback_conn->display() >= 0 || !writeback_conn->writeback())
+      continue;
+    for (DrmEncoder *writeback_enc : writeback_conn->possible_encoders()) {
+      for (DrmCrtc *possible_crtc : writeback_enc->possible_crtcs()) {
+        if (possible_crtc != display_crtc)
+          continue;
+        // Use just encoders which had not been bound already
+        if (writeback_enc->can_bind(display_crtc->display())) {
+          writeback_enc->set_crtc(display_crtc);
+          writeback_conn->set_encoder(writeback_enc);
+          writeback_conn->set_display(display_crtc->display());
+          writeback_conn->UpdateModes();
+          return 0;
+        }
+      }
+    }
+  }
+  return ret;
+}
+
 int DrmResources::CreatePropertyBlob(void *data, size_t length,
                                      uint32_t *blob_id) {
   struct drm_mode_create_blob create_blob;
diff --git a/drmresources.h b/drmresources.h
index 4cdcd87..4fb17fc 100644
--- a/drmresources.h
+++ b/drmresources.h
@@ -59,6 +59,8 @@ class DrmResources {
   }
 
   DrmConnector *GetConnectorForDisplay(int display) const;
+  DrmConnector *GetWritebackConnectorForDisplay(int display) const;
+  DrmConnector *FindWritebackConnector(int display) const;
   DrmCrtc *GetCrtcForDisplay(int display) const;
   DrmPlane *GetPlane(uint32_t id) const;
   DrmEventListener *event_listener();
@@ -84,6 +86,7 @@ class DrmResources {
                   DrmProperty *property);
 
   int CreateDisplayPipe(DrmConnector *connector);
+  int AttachWriteback(DrmConnector *display_conn);
 
   UniqueFd fd_;
   uint32_t mode_id_ = 0;
-- 
2.7.4

_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel