card: Add support for writeback connectorswriteback

Enable enumeration of writeback connectors if both libdrm and the device
support it. The new Card::has_writeback() method report if the card
support writeback connectors.

Existing code that expect all connectors to model an output may be
confused by the sudden availability of new connectors. To handle this
issue,

- add a KMSXX_DISABLE_WRITEBACK_CONNECTORS environment variable to
  disable enumeration of writeback connectors, similarly to universal
  planes ; and

- ignore writeback connectors where no specific connector is requested
  (Card::get_first_connected_connector(),
  ResourceManager::reserve_connector() if no connector name is
  specified, and applications that use all connected outputs).

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

3 files changed, 10 insertions, 1 deletions

diff --git a/utils/kmsblank.cpp b/utils/kmsblank.cpp
index 43bd2a2..2af5182 100644
--- a/utils/kmsblank.cpp
+++ b/utils/kmsblank.cpp
@@ -5,6 +5,8 @@
 #include <kms++/kms++.h>
 #include <kms++util/kms++util.h>
 
+#include <xf86drmMode.h>
+
 using namespace std;
 using namespace kms;
 
@@ -78,6 +80,9 @@ int main(int argc, char** argv)
 
 	while (true) {
 		for (Connector* conn : conns) {
+			if (conn->connector_type() == DRM_MODE_CONNECTOR_WRITEBACK)
+				continue;
+
 			if (!conn->connected()) {
 				printf("Connector %u not connected\n", conn->idx());
 				continue;
diff --git a/utils/kmstest.cpp b/utils/kmstest.cpp
index a5adbe2..cc77d14 100644
--- a/utils/kmstest.cpp
+++ b/utils/kmstest.cpp
@@ -18,6 +18,8 @@
 
 #include <kms++util/kms++util.h>
 
+#include <xf86drmMode.h>
+
 using namespace std;
 using namespace kms;
 
@@ -679,6 +681,8 @@ static vector<OutputInfo> setups_to_outputs(Card& card, ResourceManager& resman,
 	if (outputs.empty()) {
 		// no outputs defined, show a pattern on all connected screens
 		for (Connector* conn : card.get_connectors()) {
+			if (conn->connector_type() == DRM_MODE_CONNECTOR_WRITEBACK)
+				continue;
 			if (!conn->connected())
 				continue;
 
diff --git a/utils/meson.build b/utils/meson.build
index 54021d3..0bf2af5 100644
--- a/utils/meson.build
+++ b/utils/meson.build
@@ -10,7 +10,7 @@ endif
 
 utils_enabled = true
 
-common_deps = [ libkmsxx_dep, libkmsxxutil_dep ]
+common_deps = [ libkmsxx_dep, libkmsxxutil_dep, libdrm_dep ]
 
 libevdev_dep = dependency('libevdev', required : false)