[Intel-gfx] [PATCH 3/4 v6] drm/i915: wait render timeout ioctl
Ben Widawsky
ben at bwidawsk.net
Fri May 11 22:54:09 CEST 2012
This helps implement GL_ARB_sync but stops short of allowing full blown
sync objects. Finally we can use the new timed seqno waiting function
to allow userspace to wait on a buffer object with a timeout. This
implements that interface.
The IOCTL will take as input a buffer object handle, and a timeout in
nanoseconds (flags is currently optional but will likely be used for
permutations of flush operations). Users may specify 0 nanoseconds to
instantly check.
The wait ioctl with a timeout of 0 reimplements the busy ioctl. With any
non-zero timeout parameter the wait ioctl will wait for the given number
of nanoseconds on an object becoming unbusy. Since the wait itself does
so holding struct_mutex the object may become re-busied before this
completes. A similar but shorter race condition exists in the busy
ioctl.
v2: ETIME/ERESTARTSYS instead of changing to EBUSY, and EGAIN (Chris)
Flush the object from the gpu write domain (Chris + Daniel)
Fix leaked refcount in good case (Chris)
Naturally align ioctl struct (Chris)
v3: Drop lock after getting seqno to avoid ugly dance (Chris)
v4: check for 0 timeout after olr check to allow polling (Chris)
v5: Updated the comment. (Chris)
v6: Return -ETIME instead of -EBUSY when timeout_ns is 0 (Daniel)
Fix the commit message comment to be less ugly (Ben)
Add a warning to check the return timespec (Ben)
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
drivers/gpu/drm/i915/i915_dma.c | 1 +
drivers/gpu/drm/i915/i915_drv.h | 2 +
drivers/gpu/drm/i915/i915_gem.c | 86 +++++++++++++++++++++++++++++++++++++++
include/drm/i915_drm.h | 10 +++++
4 files changed, 99 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 006ea47..bd6b402 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1800,6 +1800,7 @@ struct drm_ioctl_desc i915_ioctls[] = {
DRM_IOCTL_DEF_DRV(I915_OVERLAY_ATTRS, intel_overlay_attrs, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
DRM_IOCTL_DEF_DRV(I915_SET_SPRITE_COLORKEY, intel_sprite_set_colorkey, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
DRM_IOCTL_DEF_DRV(I915_GET_SPRITE_COLORKEY, intel_sprite_get_colorkey, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+ DRM_IOCTL_DEF_DRV(I915_GEM_WAIT, i915_gem_wait_ioctl, DRM_UNLOCKED),
};
int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 83a557c..8afc673 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1226,6 +1226,8 @@ int i915_gem_get_tiling(struct drm_device *dev, void *data,
struct drm_file *file_priv);
int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
+int i915_gem_wait_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv);
void i915_gem_load(struct drm_device *dev);
int i915_gem_init_object(struct drm_gem_object *obj);
int __must_check i915_gem_flush_ring(struct intel_ring_buffer *ring,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c558bae..37ff972 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2003,6 +2003,92 @@ i915_gem_object_wait_rendering(struct drm_i915_gem_object *obj)
}
/**
+ * i915_gem_wait_ioctl - implements DRM_IOCTL_I915_GEM_WAIT
+ * @DRM_IOCTL_ARGS: standard ioctl arguments
+ *
+ * Returns 0 if successful, else an error is returned with the remaining time in
+ * the timeout parameter.
+ * -ETIME: object is still busy after timeout
+ * -ERESTARTSYS: signal interrupted the wait
+ * -ENONENT: object doesn't exist
+ * Also possible, but rare:
+ * -EAGAIN: GPU wedged
+ * -ENOMEM: damn
+ * -ENODEV: Internal IRQ fail
+ * -E?: The add request failed
+ *
+ * The wait ioctl with a timeout of 0 reimplements the busy ioctl. With any
+ * non-zero timeout parameter the wait ioctl will wait for the given number of
+ * nanoseconds on an object becoming unbusy. Since the wait itself does so
+ * without holding struct_mutex the object may become re-busied before this
+ * function completes. A similar but shorter * race condition exists in the busy
+ * ioctl
+ */
+int
+i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
+{
+ struct drm_i915_gem_wait *args = data;
+ struct drm_i915_gem_object *obj;
+ struct intel_ring_buffer *ring = NULL;
+ struct timespec timeout;
+ u32 seqno = 0;
+ int ret = 0;
+
+ timeout = ns_to_timespec(args->timeout_ns);
+
+ ret = i915_mutex_lock_interruptible(dev);
+ if (ret)
+ return ret;
+
+ obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->bo_handle));
+ if (&obj->base == NULL) {
+ mutex_unlock(&dev->struct_mutex);
+ return -ENOENT;
+ }
+
+ /* Need to make sure the object is flushed first. This non-obvious
+ * flush is required to enforce that (active && !olr) == no wait
+ * necessary.
+ */
+ ret = i915_gem_object_flush_gpu_write_domain(obj);
+ if (ret)
+ goto out;
+
+ if (obj->active) {
+ seqno = obj->last_rendering_seqno;
+ ring = obj->ring;
+ }
+
+ if (seqno == 0)
+ goto out;
+
+ ret = i915_gem_check_olr(ring, seqno);
+ if (ret)
+ goto out;
+
+ /* Do this after OLR check to make sure we make forward progress polling
+ * on this IOCTL with a 0 timeout (like busy ioctl)
+ */
+ if (!args->timeout_ns) {
+ ret = -ETIME;
+ goto out;
+ }
+
+ drm_gem_object_unreference(&obj->base);
+ mutex_unlock(&dev->struct_mutex);
+
+ ret = __wait_seqno(ring, seqno, true, &timeout);
+ WARN_ON(!timespec_valid(&timeout));
+ args->timeout_ns = timespec_to_ns(&timeout);
+ return ret;
+
+out:
+ drm_gem_object_unreference(&obj->base);
+ mutex_unlock(&dev->struct_mutex);
+ return ret;
+}
+
+/**
* i915_gem_object_sync - sync an object to a ring.
*
* @obj: object which may be in use on another ring.
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index f3f8224..bab1743 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -200,6 +200,7 @@ typedef struct _drm_i915_sarea {
#define DRM_I915_GEM_EXECBUFFER2 0x29
#define DRM_I915_GET_SPRITE_COLORKEY 0x2a
#define DRM_I915_SET_SPRITE_COLORKEY 0x2b
+#define DRM_I915_GEM_WAIT 0x2c
#define DRM_IOCTL_I915_INIT DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
#define DRM_IOCTL_I915_FLUSH DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -243,6 +244,7 @@ typedef struct _drm_i915_sarea {
#define DRM_IOCTL_I915_OVERLAY_ATTRS DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_OVERLAY_ATTRS, struct drm_intel_overlay_attrs)
#define DRM_IOCTL_I915_SET_SPRITE_COLORKEY DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_SET_SPRITE_COLORKEY, struct drm_intel_sprite_colorkey)
#define DRM_IOCTL_I915_GET_SPRITE_COLORKEY DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_SET_SPRITE_COLORKEY, struct drm_intel_sprite_colorkey)
+#define DRM_IOCTL_I915_GEM_WAIT DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_WAIT, struct drm_i915_gem_wait)
/* Allow drivers to submit batchbuffers directly to hardware, relying
* on the security mechanisms provided by hardware.
@@ -886,4 +888,12 @@ struct drm_intel_sprite_colorkey {
__u32 flags;
};
+struct drm_i915_gem_wait {
+ /** Handle of BO we shall wait on */
+ __u32 bo_handle;
+ __u32 flags;
+ /** Number of nanoseconds to wait, Returns time remaining. */
+ __u64 timeout_ns;
+};
+
#endif /* _I915_DRM_H_ */
--
1.7.10.1
More information about the Intel-gfx
mailing list