libkms++: dumbframebuffer: Get file descriptor for the FB

v4l linux needs file descriptor instead of handle.

2 files changed, 21 insertions, 1 deletions

diff --git a/libkms++/dumbframebuffer.cpp b/libkms++/dumbframebuffer.cpp
index 0779b05..46a6e5a 100644
--- a/libkms++/dumbframebuffer.cpp
+++ b/libkms++/dumbframebuffer.cpp
@@ -4,6 +4,8 @@
 #include <sys/mman.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
+#include <fcntl.h>
+#include <unistd.h>
 #include <drm_fourcc.h>
 #include <drm.h>
 #include <drm_mode.h>
@@ -33,6 +35,19 @@ DumbFramebuffer::~DumbFramebuffer()
 	Destroy();
 }
 
+uint32_t DumbFramebuffer::prime_fd(unsigned int plane)
+{
+	if (m_planes[plane].prime_fd >= 0)
+		return m_planes[plane].prime_fd;
+
+	int r = drmPrimeHandleToFD(card().fd(), m_planes[plane].handle,
+				   DRM_CLOEXEC, &m_planes[plane].prime_fd);
+	if (r)
+		throw std::runtime_error("drmPrimeHandleToFD failed\n");
+
+	return m_planes[plane].prime_fd;
+}
+
 struct FormatPlaneInfo
 {
 	uint8_t bitspp;	/* bits per (macro) pixel */
@@ -110,6 +125,8 @@ void DumbFramebuffer::Create()
 
 		/* clear the framebuffer to 0 */
 		memset(plane.map, 0, plane.size);
+
+		plane.prime_fd = -1;
 	}
 
 	/* create framebuffer object for the dumb-buffer */
@@ -140,7 +157,8 @@ void DumbFramebuffer::Destroy()
 		struct drm_mode_destroy_dumb dreq = drm_mode_destroy_dumb();
 		dreq.handle = plane.handle;
 		drmIoctl(card().fd(), DRM_IOCTL_MODE_DESTROY_DUMB, &dreq);
-
+		if (plane.prime_fd >= 0)
+			::close(plane.prime_fd);
 	}
 }
 
diff --git a/libkms++/dumbframebuffer.h b/libkms++/dumbframebuffer.h
index 0ee0406..51f5123 100644
--- a/libkms++/dumbframebuffer.h
+++ b/libkms++/dumbframebuffer.h
@@ -20,12 +20,14 @@ public:
 	uint32_t stride(unsigned plane) const { return m_planes[plane].stride; }
 	uint32_t size(unsigned plane) const { return m_planes[plane].size; }
 	uint32_t offset(unsigned plane) const { return m_planes[plane].offset; }
+	uint32_t prime_fd(unsigned plane);
 
 	void clear();
 
 private:
 	struct FramebufferPlane {
 		uint32_t handle;
+		int prime_fd;
 		uint32_t size;
 		uint32_t stride;
 		uint32_t offset;