Re: [RFC PATCH 7/7] drm/prime: Support explicit fence on export

On 26-09-14 12:00, Lauri Peltonen wrote:

Allow user space to provide an explicit sync fence fd when exporting a dma-buf from gem handle. The fence will be stored as the explicit fence to the reservation object.

Signed-off-by: Lauri Peltonen lpeltonen@nvidia.com

drivers/gpu/drm/drm_prime.c | 41 +++++++++++++++++++++++++++++++++-------- include/uapi/drm/drm.h | 9 ++++++++- 2 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 2807a77..c69df2e 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -28,8 +28,10 @@

#include <linux/export.h> #include <linux/dma-buf.h> +#include <linux/reservation.h> #include <drm/drmP.h> #include "drm_internal.h" +#include "../../staging/android/sync.h"

/*

• DMA-BUF/GEM Object references and lifetime overview:

@@ -329,7 +331,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {

• drm_gem_prime_export - helper library implemention of the export callback
• @dev: drm_device to export from
• @obj: GEM object to export

• • @flags: flags like DRM_CLOEXEC

• • @flags: flags like DRM_CLOEXEC or DRM_SYNC_FD
  • This is the implementation of the gem_prime_export functions for GEM drivers
  • using the PRIME helpers.

@@ -385,7 +387,7 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,

• @dev: dev to export the buffer from
• @file_priv: drm file-private structure
• @handle: buffer handle to export

• • @flags: flags like DRM_CLOEXEC

• • @flags: flags like DRM_CLOEXEC or DRM_SYNC_FD
  • @prime_fd: pointer to storage for the fd id of the create dma-buf
  • This is the PRIME export function which must be used mandatorily by GEM

@@ -401,6 +403,24 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev, struct drm_gem_object *obj; int ret = 0; struct dma_buf *dmabuf;

• struct fence *fence = NULL;
• if (flags & DRM_SYNC_FD) {

+#ifdef CONFIG_SYNC

• struct sync_fence *sf = sync_fence_fdget(*prime_fd);
  

• if (!sf)
  

• 	return -ENOENT;
  

• if (sf->num_fences != 1) {
  

• 	sync_fence_put(sf);
  

• 	return -EINVAL;
  

• }
  

• fence = fence_get(sf->cbs[0].sync_pt);
  

• sync_fence_put(sf);
  

• flags &= ~DRM_SYNC_FD;
  

+#else

• return -ENODEV;
  

+#endif

• }

  mutex_lock(&file_priv->prime.lock); obj = drm_gem_object_lookup(dev, file_priv, handle);

@@ -453,6 +473,14 @@ out_have_obj: goto fail_put_dmabuf;

out_have_handle:

• if (fence) {

• if (!dmabuf->resv) {
  

• 	ret = -ENODEV;
  

• 	goto fail_put_dmabuf;
  

• }
  

This is never true. A default resv gets allocated, see dma_buf's create function.

~Maarten

~Maarten