Commit 23ba4fd0 authored by Ben Widawsky's avatar Ben Widawsky Committed by Daniel Vetter
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drm/i915: wait render timeout ioctl



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)

v7: Use DRM_AUTH for the ioctl. (Eugeni)
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent f3fd3768
......@@ -1803,6 +1803,7 @@ 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_AUTH|DRM_UNLOCKED),
};
int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);
......
......@@ -1229,6 +1229,8 @@ 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,
......
......@@ -2000,6 +2000,92 @@ i915_gem_object_wait_rendering(struct drm_i915_gem_object *obj)
return 0;
}
/**
* 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.
*
......
......@@ -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_ */
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