From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Engine discovery query allows userspace to enumerate engines, probe
their
configuration features, all without needing to maintain the internal
PCI
ID based database.
A new query for the generic i915 query ioctl is added named
DRM_I915_QUERY_ENGINE_INFO, together with accompanying structure
drm_i915_query_engine_info. The address of latter should be passed
to the
kernel in the query.data_ptr field, and should be large enough for the
kernel to fill out all known engines as struct drm_i915_engine_info
elements trailing the query.
As with other queries, setting the item query length to zero allows
userspace to query minimum required buffer size.
Enumerated engines have common type mask which can be used to query all
hardware engines, versus engines userspace can submit to using the
execbuf
uAPI.
Engines also have capabilities which are per engine class namespace of
bits describing features not present on all engine instances.
v2:
* Fixed HEVC assignment.
* Reorder some fields, rename type to flags, increase width. (Lionel)
* No need to allocate temporary storage if we do it engine by engine.
(Lionel)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@xxxxxxxxx>
Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
This is RFC for now since it is not very usable before the new
execbuf API
or virtual engine queue submission gets closer.
In this version I have added capability of distinguishing between
hardware
engines and ABI engines. This is to account for probable future use
cases
like virtualization, where guest might only see one engine instance,
but
will want to know overall hardware capabilities in order to tune its
behaviour.
In general I think we will have to wait a bit before defining the final
look of the uAPI, but in the meantime I thought it useful to share
as RFC.
---
drivers/gpu/drm/i915/i915_query.c | 63
+++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_engine_cs.c | 2 ++
drivers/gpu/drm/i915/intel_ringbuffer.h | 3 ++
include/uapi/drm/i915_drm.h | 46 ++++++++++++++++++++++++
4 files changed, 114 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_query.c
b/drivers/gpu/drm/i915/i915_query.c
index 3ace929dd90f..a1c0e3acc882 100644
--- a/drivers/gpu/drm/i915/i915_query.c
+++ b/drivers/gpu/drm/i915/i915_query.c
@@ -82,9 +82,72 @@ static int query_topology_info(struct
drm_i915_private *dev_priv,
return total_length;
}
+static int
+query_engine_info(struct drm_i915_private *i915,
+ struct drm_i915_query_item *query_item)
+{
+ struct drm_i915_query_engine_info __user *query_ptr =
+ u64_to_user_ptr(query_item->data_ptr);
+ struct drm_i915_engine_info __user *info_ptr =
&query_ptr->engines[0];
+ struct drm_i915_query_engine_info query;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ int len;
+
+ if (query_item->flags)
+ return -EINVAL;
+
+ len = sizeof(struct drm_i915_query_engine_info) +
+ I915_NUM_ENGINES * sizeof(struct drm_i915_engine_info);
+
+ if (!query_item->length)
+ return len;
+ else if (query_item->length < len)
+ return -EINVAL;
+
+ if (copy_from_user(&query, query_ptr, sizeof(query)))
+ return -EFAULT;
+
+ if (query.num_engines || query.rsvd[0] || query.rsvd[1] ||
+ query.rsvd[2])
+ return -EINVAL;
+
+ if (!access_ok(VERIFY_WRITE, query_ptr, query_item->length))
