Re: [Intel-gfx] [PATCH 09/27] drm/i915: Expose logical engine instance to user

John Harrison
2021-09-13T23:06:44Z

On 8/20/2021 15:44, Matthew Brost wrote:
> Expose logical engine instance to user via query engine info IOCTL. This
> is required for split-frame workloads as these needs to be placed on
> engines in a logically contiguous order. The logical mapping can change
> based on fusing. Rather than having user have knowledge of the fusing we
> simply just expose the logical mapping with the existing query engine
> info IOCTL.
>
> IGT: https://patchwork.freedesktop.org/patch/445637/?series=92854&rev=1
> media UMD: link coming soon
>
> v2:
> (Daniel Vetter)
> - Add IGT link, placeholder for media UMD
>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
> drivers/gpu/drm/i915/i915_query.c | 2 ++
> include/uapi/drm/i915_drm.h | 8 +++++++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index e49da36c62fb..8a72923fbdba 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -124,7 +124,9 @@ query_engine_info(struct drm_i915_private *i915,
> for_each_uabi_engine(engine, i915) {
> info.engine.engine_class = engine->uabi_class;
> info.engine.engine_instance = engine->uabi_instance;
> + info.flags = I915_ENGINE_INFO_HAS_LOGICAL_INSTANCE;
> info.capabilities = engine->uabi_capabilities;
> + info.logical_instance = ilog2(engine->logical_mask);
>
> if (copy_to_user(info_ptr, &info, sizeof(info)))
> return -EFAULT;
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index bde5860b3686..b1248a67b4f8 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -2726,14 +2726,20 @@ struct drm_i915_engine_info {
>
> /** @flags: Engine flags. */
> __u64 flags;
> +#define I915_ENGINE_INFO_HAS_LOGICAL_INSTANCE (1 << 0)
>
> /** @capabilities: Capabilities of this engine. */
> __u64 capabilities;
> #define I915_VIDEO_CLASS_CAPABILITY_HEVC (1 << 0)
> #define I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC (1 << 1)
>
> + /** @logical_instance: Logical instance of engine */
> + __u16 logical_instance;
> +
> /** @rsvd1: Reserved fields. */
> - __u64 rsvd1[4];
> + __u16 rsvd1[3];
> + /** @rsvd2: Reserved fields. */
> + __u64 rsvd2[3];
> };
>
> /**
Any idea why the padding? Would be useful if the comment said 'this
structure must be at least/exactly X bytes in size / a multiple of X
bytes in size because ...' or whatever.

However, not really anything to do with this patch as such, so either way:
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>