card: add factory function for selecting card by name

Uses drmOpen() to do the heavy lifting.

2 files changed, 12 insertions, 0 deletions

diff --git a/kms++/inc/kms++/card.h b/kms++/inc/kms++/card.h
index 9ca06b2..5c1cf7c 100644
--- a/kms++/inc/kms++/card.h
+++ b/kms++/inc/kms++/card.h
@@ -24,6 +24,8 @@ class Card
 {
 	friend class Framebuffer;
 public:
+	static std::unique_ptr<Card> open_named_card(const std::string& name);
+
 	Card(const std::string& dev_path = "");
 	Card(const std::string& driver, uint32_t idx);
 	Card(int fd, bool take_ownership);
diff --git a/kms++/src/card.cpp b/kms++/src/card.cpp
index 062645a..527aca6 100644
--- a/kms++/src/card.cpp
+++ b/kms++/src/card.cpp
@@ -104,6 +104,16 @@ static int open_device_by_driver(string name, uint32_t idx)
 	throw invalid_argument("Failed to find a DRM device " + name + ":" + to_string(idx));
 }
 
+std::unique_ptr<Card> Card::open_named_card(const std::string& name)
+{
+	int fd = drmOpen(name.c_str(), 0);
+
+	if (fd < 0)
+		throw invalid_argument(string(strerror(errno)) + " opening card \"" + name + "\"");
+
+	return std::unique_ptr<Card>(new Card(fd, true));
+}
+
 Card::Card(const std::string& dev_path)
 {
 	const char* drv_p = getenv("KMSXX_DRIVER");