Hold client buffers till KMS stops using them

src/drm.cpp

@@ -13,6 +13,10 @@
 #include <sys/select.h>
 #include <signal.h>
 
+extern "C" {
+#include <wlr/types/wlr_buffer.h>
+}
+
 #include "drm.hpp"
 #include "main.hpp"
 #include "vblankmanager.hpp"
@@ -631,7 +635,7 @@ int drm_atomic_commit(struct drm_t *drm, struct Composite_t *pComposite, struct
 	return ret;
 }
 
-uint32_t drm_fbid_from_dmabuf( struct drm_t *drm, struct wlr_dmabuf_attributes *dma_buf )
+uint32_t drm_fbid_from_dmabuf( struct drm_t *drm, struct wlr_buffer *buf, struct wlr_dmabuf_attributes *dma_buf )
 {
 	assert( dma_buf->n_planes == 1);
 
@@ -655,7 +659,15 @@ uint32_t drm_fbid_from_dmabuf( struct drm_t *drm, struct wlr_dmabuf_attributes *
 	}
 	assert( drm->map_fbid_inflightflips[ fb_id ].held == false );
 
+	if ( buf != nullptr )
+	{
+		wlserver_lock();
+		buf = wlr_buffer_lock( buf );
+		wlserver_unlock();
+	}
+
 	drm->map_fbid_inflightflips[ fb_id ].id = fb_id;
+	drm->map_fbid_inflightflips[ fb_id ].buf = buf;
 	drm->map_fbid_inflightflips[ fb_id ].held = true;
 	drm->map_fbid_inflightflips[ fb_id ].n_refs = 0;
 
@@ -672,6 +684,13 @@ static void drm_free_fb( struct drm_t *drm, struct fb *fb )
 		perror( "drmModeRmFB failed" );
 	}
 
+	if ( fb->buf != nullptr )
+	{
+		wlserver_lock();
+		wlr_buffer_unlock( fb->buf );
+		wlserver_unlock();
+	}
+
 	fb = {};
 }
 

src/drm.hpp

@@ -13,6 +13,7 @@ extern "C" {
 }
 
 #include "rendervulkan.hpp"
+#include "wlserver.h"
 
 #include <unordered_map>
 #include <utility>
@@ -40,6 +41,8 @@ struct connector {
 
 struct fb {
 	uint32_t id;
+	/* Client buffer, if any */
+	struct wlr_buffer *buf;
 	/* A FB is held if it's being used by steamcompmgr */
 	bool held;
 	/* Number of page-flips using the FB */
@@ -97,6 +100,6 @@ extern bool g_bDebugLayers;
 
 int init_drm(struct drm_t *drm, const char *device, const char *mode_str, unsigned int vrefresh);
 int drm_atomic_commit(struct drm_t *drm, struct Composite_t *pComposite, struct VulkanPipeline_t *pPipeline );
-uint32_t drm_fbid_from_dmabuf( struct drm_t *drm, struct wlr_dmabuf_attributes *dma_buf );
+uint32_t drm_fbid_from_dmabuf( struct drm_t *drm, struct wlr_buffer *buf, struct wlr_dmabuf_attributes *dma_buf );
 void drm_drop_fbid( struct drm_t *drm, uint32_t fbid );
 bool drm_can_avoid_composite( struct drm_t *drm, struct Composite_t *pComposite, struct VulkanPipeline_t *pPipeline );

src/rendervulkan.cpp

@@ -347,6 +347,7 @@ bool CVulkanTexture::BInit( uint32_t width, uint32_t height, VkFormat format, bo
 		// We assume we own the memory when doing this right now.
 		// We could support the import scenario as well if needed
 // 		assert( bTextureable == false );
+		assert( pDMA == nullptr );
 
 		m_DMA.modifier = DRM_FORMAT_MOD_INVALID;
 		m_DMA.n_planes = 1;
@@ -376,7 +377,7 @@ bool CVulkanTexture::BInit( uint32_t width, uint32_t height, VkFormat format, bo
 
 		m_DMA.stride[0] = image_layout.rowPitch;
 
-		m_FBID = drm_fbid_from_dmabuf( &g_DRM, &m_DMA );
+		m_FBID = drm_fbid_from_dmabuf( &g_DRM, nullptr, &m_DMA );
 
 		if ( m_FBID == 0 )
 			return false;

src/steamcompmgr.cpp

@@ -521,7 +521,7 @@ import_commit ( struct wlr_buffer *buf, struct wlr_dmabuf_attributes *dmabuf, co
 
 	if ( BIsNested() == False )
 	{
-		commit.fb_id = drm_fbid_from_dmabuf( &g_DRM, dmabuf );
+		commit.fb_id = drm_fbid_from_dmabuf( &g_DRM, buf, dmabuf );
 		assert( commit.fb_id != 0 );
 	}