path: root/include/uapi/drm/i915_drm.h
diff options
authorLionel Landwerlin <>2018-03-06 12:28:56 +0000
committerLionel Landwerlin <>2018-03-08 10:07:18 +0000
commita446ae2c6e6555048301f2339cfd97b8eed6d0b7 (patch)
treedd8949798f2533a6fa7875d6b2ca3eda2361637c /include/uapi/drm/i915_drm.h
parentcac6cfaa2fe4f9be753daeefd523ebcc0f46e331 (diff)
drm/i915: add query uAPI
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) v10: Typos & comments in uapi (Joonas) Signed-off-by: Lionel Landwerlin <> Reviewed-by: Tvrtko Ursulin <> Acked-by: Chris Wilson <> Reviewed-by: Joonas Lahtinen <> Link:
Diffstat (limited to 'include/uapi/drm/i915_drm.h')
1 files changed, 43 insertions, 3 deletions
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 29fa48e4755d..eedd5a23a944 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -318,6 +318,7 @@ typedef struct _drm_i915_sarea {
#define DRM_I915_PERF_OPEN 0x36
#define DRM_I915_PERF_ADD_CONFIG 0x37
#define DRM_I915_PERF_REMOVE_CONFIG 0x38
+#define DRM_I915_QUERY 0x39
#define DRM_IOCTL_I915_INIT DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
@@ -375,6 +376,7 @@ typedef struct _drm_i915_sarea {
#define DRM_IOCTL_I915_PERF_OPEN DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_OPEN, struct drm_i915_perf_open_param)
#define DRM_IOCTL_I915_PERF_ADD_CONFIG DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_ADD_CONFIG, struct drm_i915_perf_oa_config)
+#define DRM_IOCTL_I915_QUERY DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_QUERY, struct drm_i915_query)
/* Allow drivers to submit batchbuffers directly to hardware, relying
* on the security mechanisms provided by hardware.
@@ -1606,15 +1608,53 @@ struct drm_i915_perf_oa_config {
__u32 n_flex_regs;
- * These fields are pointers to tuples of u32 values (register
- * address, value). For example the expected length of the buffer
- * pointed by mux_regs_ptr is (2 * sizeof(u32) * n_mux_regs).
+ * These fields are pointers to tuples of u32 values (register address,
+ * value). For example the expected length of the buffer pointed by
+ * mux_regs_ptr is (2 * sizeof(u32) * n_mux_regs).
__u64 mux_regs_ptr;
__u64 boolean_regs_ptr;
__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 sets this
+ * value to a negative value to signal an error on a particular query
+ * item.
+ */
+ __s32 length;
+ /*
+ * Unused for 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. Must be cleared to zero.
+ */
+ __u32 flags;
+ /*
+ * This points to an array of num_items drm_i915_query_item structures.
+ */
+ __u64 items_ptr;
#if defined(__cplusplus)