On 11/09/14 12:52, Chris Wilson wrote:
On Thu, Sep 11, 2014 at 12:33:41PM +0100, Lionel Landwerlin wrote:
When using Mesa and LibVA in the same process, one would like to be
able bind buffers from the output of the decoder to a GL texture
through an EGLImage.
LibVA can reuse buffers allocated by Gbm through a file descriptor. It
will then wrap it into a drm_intel_bo with
drm_intel_bo_gem_create_from_prime().
Given both libraries are using libdrm to allocate and use buffer
objects, there is a need to have the buffer objects properly
refcounted. That is possible if both API use the same drm_intel_bo
objects, but that also requires that both API use the same
drm_intel_bufmgr object.
The description is wrong though. Reusing buffers export and import
through a dmabuf, should work and be correctly refcounted already.
This patch adds the ability to use the same /dev/dri/card0 device fd
between two libraries. This implies that they share the same context and
address space, which is probably not what you want, but nevertheless
seems sensible if they are sharing the device fd in the first place.
That's what I meant, sorry if it was unclear.
I suspect this may break unwary users such as igt, which would fork
after creating a bufmgr, close the fds, but then open their own device
fd with the same fd as before. Not a huge issue, just something to check
in case it causes some fun fallout.
Will have a look, thanks.
This patch modifies drm_intel_bufmgr_gem_init() so given a file
descriptor, it will look for an already existing drm_intel_bufmgr
using the same file descriptor and return that object.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
---
intel/intel_bufmgr_gem.c | 100 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 88 insertions(+), 12 deletions(-)
diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index 0e1cb0d..125c81c 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -94,6 +94,8 @@ struct drm_intel_gem_bo_bucket {
typedef struct _drm_intel_bufmgr_gem {
drm_intel_bufmgr bufmgr;
+ atomic_t refcount;
+
int fd;
int max_relocs;
@@ -3186,6 +3188,85 @@ drm_intel_bufmgr_gem_set_aub_annotations(drm_intel_bo *bo,
bo_gem->aub_annotation_count = count;
}
+static pthread_mutex_t bufmgr_list_mutex = PTHREAD_MUTEX_INITIALIZER;
+static drm_intel_bufmgr_gem **bufmgr_list = NULL;
+static unsigned bufmgr_list_size = 0, bufmgr_list_nb;
+
+static drm_intel_bufmgr_gem *
+drm_intel_bufmgr_gem_find_or_create_for_fd(int fd, int *found)
+{
+ drm_intel_bufmgr_gem *bufmgr_gem;
+
+ assert(pthread_mutex_lock(&bufmgr_list_mutex) == 0);
+
+ if (bufmgr_list == NULL) {
Just use an embedded list rather than array, that would greatly simplify
the search, cration and deletion.
-Chris
I tried to use the embedded list, but from my understanding I need the
embedded structure at the top of the bufmgr struct. Is that possible?
Sounds like an ABI break.
Thanks,
-
Lionel
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