Call drm_gem_prime_handle_to_fd() and drm_gem_prime_fd_to_handle() by
default if no PRIME import/export helpers have been set. Both functions
are the default for almost all drivers.
DRM drivers implement struct drm_driver.gem_prime_import_sg_table
to import dma-buf objects from other drivers. Having the function
drm_gem_prime_fd_to_handle() functions set by default allows each
driver to import dma-buf objects to itself, even without support for
other drivers.
For drm_gem_prime_handle_to_fd() it is similar: using it by default
allows each driver to export to itself, even without support for other
drivers.
This functionality enables userspace to share per-driver buffers
across process boundaries via PRIME (e.g., wlroots requires this
functionality). The patch generalizes a pattern that has previously
been implemented by GEM VRAM helpers [1] to work with any driver.
For example, gma500 can now run the wlroots-based sway compositor.
v2:
* clean up docs and TODO comments (Simon, Zack)
* clean up style in drm_getcap()
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
Link:
https://lore.kernel.org/dri-devel/20230302143502.500661-1-cont...@emersion.fr/
# 1
Reviewed-by: Simon Ser <cont...@emersion.fr>
Acked-by: Alex Deucher <alexander.deuc...@amd.com>
---
drivers/gpu/drm/drm_ioctl.c | 3 +--
drivers/gpu/drm/drm_prime.c | 21 ++++++++++++---------
include/drm/drm_drv.h | 12 ++----------
3 files changed, 15 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 7c9d66ee917de..8e9afe7af19c9 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -245,8 +245,7 @@ static int drm_getcap(struct drm_device *dev, void *data,
struct drm_file *file_
req->value = 1;
return 0;
case DRM_CAP_PRIME:
- req->value |= dev->driver->prime_fd_to_handle ?
DRM_PRIME_CAP_IMPORT : 0;
- req->value |= dev->driver->prime_handle_to_fd ?
DRM_PRIME_CAP_EXPORT : 0;
+ req->value = DRM_PRIME_CAP_IMPORT | DRM_PRIME_CAP_EXPORT;
return 0;
case DRM_CAP_SYNCOBJ:
req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 6bcf324ef81c9..27a41d5e11d75 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -372,11 +372,12 @@ int drm_prime_fd_to_handle_ioctl(struct drm_device *dev,
void *data,
{
struct drm_prime_handle *args = data;
- if (!dev->driver->prime_fd_to_handle)
- return -ENOSYS;
+ if (dev->driver->prime_fd_to_handle) {
+ return dev->driver->prime_fd_to_handle(dev, file_priv, args->fd,
+ &args->handle);
+ }
- return dev->driver->prime_fd_to_handle(dev, file_priv,
- args->fd, &args->handle);
+ return drm_gem_prime_fd_to_handle(dev, file_priv, args->fd,
&args->handle);
}
static struct dma_buf *export_and_register_object(struct drm_device *dev,
@@ -518,15 +519,17 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev,
void *data,
{
struct drm_prime_handle *args = data;
- if (!dev->driver->prime_handle_to_fd)
- return -ENOSYS;
-
/* check flags are valid */
if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
return -EINVAL;
- return dev->driver->prime_handle_to_fd(dev, file_priv,
- args->handle, args->flags, &args->fd);
+ if (dev->driver->prime_handle_to_fd) {
+ return dev->driver->prime_handle_to_fd(dev, file_priv,
+ args->handle,
args->flags,
+ &args->fd);
+ }
+ return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
+ args->flags, &args->fd);
}
/**
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 870278ecd8ba9..b77f2c7275b76 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -304,22 +304,14 @@ struct drm_driver {
/**
* @prime_handle_to_fd:
*
- * Main PRIME export function. Should be implemented with
- * drm_gem_prime_handle_to_fd() for GEM based drivers.
- *
- * For an in-depth discussion see :ref:`PRIME buffer sharing
- * documentation <prime_buffer_sharing>`.
+ * PRIME export function. Only used by vmwgfx.
*/
int (*prime_handle_to_fd)(struct drm_device *dev, struct drm_file
*file_priv,
uint32_t handle, uint32_t flags, int *prime_fd);
/**
* @prime_fd_to_handle:
*
- * Main PRIME import function. Should be implemented with
- * drm_gem_prime_fd_to_handle() for GEM based drivers.
- *
- * For an in-depth discussion see :ref:`PRIME buffer sharing
- * documentation <prime_buffer_sharing>`.
+ * PRIME import function. Only used by vmwgfx.
*/
int (*prime_fd_to_handle)(struct drm_device *dev, struct drm_file
*file_priv,
int prime_fd, uint32_t *handle);
--
2.41.0
