On 05/03/18 14:54, Joonas Lahtinen wrote:
Quoting Lionel Landwerlin (2018-02-22 19:53:58)
There are a number of information that are readable from hardware
registers and that we would like to make accessible to userspace. One
particular example is the topology of the execution units (how are
execution units grouped in subslices and slices and also which ones
have been fused off for die recovery).
At the moment the GET_PARAM ioctl covers some basic needs, but
generally is only able to return a single value for each defined
parameter. This is a bit problematic with topology descriptions which
are array/maps of available units.
This change introduces a new ioctl that can deal with requests to fill
structures of potentially variable lengths. The user is expected fill
a query with length fields set at 0 on the first call, the kernel then
sets the length fields to the their expected values. A second call to
the kernel with length fields at their expected values will trigger a
copy of the data to the pointed memory locations.
The scope of this uAPI is only to provide information to userspace,
not to allow configuration of the device.
v2: Simplify dispatcher code iteration (Tvrtko)
Tweak uapi drm_i915_query_item structure (Tvrtko)
v3: Rename pad fields into flags (Chris)
Return error on flags field != 0 (Chris)
Only copy length back to userspace in drm_i915_query_item (Chris)
v4: Use array of functions instead of switch (Chris)
v5: More comments in uapi (Tvrtko)
Return query item errors in length field (All)
v6: Tweak uapi comments style to match the coding style (Lionel)
v7: Add i915_query.h (Joonas)
v8: (Lionel) Change the behavior of the item iterator to report
invalid queries into the query item rather than stopping the
iteration. This enables userspace applications to query newer
items on older kernels and only have failure on the items that are
not supported.
v9: Edit copyright headers (Joonas)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Acked-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
<SNIP>
@@ -1615,6 +1617,44 @@ struct drm_i915_perf_oa_config {
__u64 flex_regs_ptr;
};
+struct drm_i915_query_item {
+ __u64 query_id;
+
+ /*
+ * When set to zero by userspace, this is filled with the size of the
+ * data to be written at the data_ptr pointer. The kernel set this
"sets"
+ * value to a negative value to signal an error on a particular query
+ * item.
+ */
+ __s32 length;
+
+ /*
+ * Unused for now.
"now. Must be cleared to zero."
+ */
+ __u32 flags;
+
+ /*
+ * Data will be written at the location pointed by data_ptr when the
+ * value of length matches the length of the data to be written by the
+ * kernel.
+ */
+ __u64 data_ptr;
+};
+
+struct drm_i915_query {
+ __u32 num_items;
+
+ /*
+ * Unused for now.
Ditto.
+ */
+ __u32 flags;
+
+ /*
+ * This point to an array of num_items drm_i915_query_item structures.
"points"
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Lets wait for the Mesa patch review still before merging.
Regards, Joonas
Thanks, applied locally.
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