From d59e75eef52d89201aaf5342a3ac23ddf3e9b112 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Mon, 2 Oct 2023 15:46:48 +0200 Subject: drm/nouveau: exec: report max pushs through getparam Report the maximum number of IBs that can be pushed with a single DRM_IOCTL_NOUVEAU_EXEC through DRM_IOCTL_NOUVEAU_GETPARAM. While the maximum number of IBs per ring might vary between chipsets, the kernel will make sure that userspace can only push a fraction of the maximum number of IBs per ring per job, such that we avoid a situation where there's only a single job occupying the ring, which could potentially lead to the ring run dry. Using DRM_IOCTL_NOUVEAU_GETPARAM to report the maximum number of IBs that can be pushed with a single DRM_IOCTL_NOUVEAU_EXEC implies that all channels of a given device have the same ring size. Reviewed-by: Dave Airlie Reviewed-by: Lyude Paul Acked-by: Faith Ekstrand Signed-off-by: Danilo Krummrich Link: https://patchwork.freedesktop.org/patch/msgid/20231002135008.10651-3-dakr@redhat.com --- include/uapi/drm/nouveau_drm.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/drm/nouveau_drm.h b/include/uapi/drm/nouveau_drm.h index 8d7402c13e56..eaf9f248619f 100644 --- a/include/uapi/drm/nouveau_drm.h +++ b/include/uapi/drm/nouveau_drm.h @@ -44,6 +44,16 @@ extern "C" { #define NOUVEAU_GETPARAM_PTIMER_TIME 14 #define NOUVEAU_GETPARAM_HAS_BO_USAGE 15 #define NOUVEAU_GETPARAM_HAS_PAGEFLIP 16 + +/** + * @NOUVEAU_GETPARAM_EXEC_PUSH_MAX + * + * Query the maximum amount of IBs that can be pushed through a single + * &drm_nouveau_exec structure and hence a single &DRM_IOCTL_NOUVEAU_EXEC + * ioctl(). + */ +#define NOUVEAU_GETPARAM_EXEC_PUSH_MAX 17 + struct drm_nouveau_getparam { __u64 param; __u64 value; -- cgit v1.2.3