From 2949ab59982d98097a6dbae48c7c5acb8ce5992c Mon Sep 17 00:00:00 2001
From: Peeter Must <karu.pruun@gmail.com>
Date: Thu, 23 Jan 2020 10:43:48 +0200
Subject: [PATCH] drm: Pass CRTC ID in userspace vblank events

* Add DRM_CAP_CRTC_IN_VBLANK_EVENT so userspace can
  query the crtc field.

* This follows Linux's commit
  5db06a8a98f515f67446a69c57577c4c363ec65d.
---
 sys/dev/drm/drm_ioctl.c            | 3 +++
 sys/dev/drm/drm_irq.c              | 2 ++
 sys/dev/drm/include/uapi/drm/drm.h | 3 ++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/sys/dev/drm/drm_ioctl.c b/sys/dev/drm/drm_ioctl.c
index 2d9951561a..63756af24c 100644
--- a/sys/dev/drm/drm_ioctl.c
+++ b/sys/dev/drm/drm_ioctl.c
@@ -265,6 +265,9 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 	case DRM_CAP_ADDFB2_MODIFIERS:
 		req->value = dev->mode_config.allow_fb_modifiers;
 		break;
+	case DRM_CAP_CRTC_IN_VBLANK_EVENT:
+		req->value = 1;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/sys/dev/drm/drm_irq.c b/sys/dev/drm/drm_irq.c
index 59e86a986d..fdf21ea8be 100644
--- a/sys/dev/drm/drm_irq.c
+++ b/sys/dev/drm/drm_irq.c
@@ -1040,6 +1040,7 @@ void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
 
 	e->pipe = pipe;
 	e->event.sequence = drm_vblank_count(dev, pipe);
+	e->event.crtc_id = crtc->base.id;
 	list_add_tail(&e->base.link, &dev->vblank_event_list);
 }
 EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
@@ -1070,6 +1071,7 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 		now = get_drm_timestamp();
 	}
 	e->pipe = pipe;
+	e->event.crtc_id = crtc->base.id;
 	send_vblank_event(dev, e, seq, &now);
 }
 EXPORT_SYMBOL(drm_crtc_send_vblank_event);
diff --git a/sys/dev/drm/include/uapi/drm/drm.h b/sys/dev/drm/include/uapi/drm/drm.h
index d71c747349..3d065caca7 100644
--- a/sys/dev/drm/include/uapi/drm/drm.h
+++ b/sys/dev/drm/include/uapi/drm/drm.h
@@ -641,6 +641,7 @@ struct drm_gem_open {
 #define DRM_CAP_CURSOR_HEIGHT		0x9
 #define DRM_CAP_ADDFB2_MODIFIERS	0x10
 #define DRM_CAP_PAGE_FLIP_TARGET	0x11
+#define DRM_CAP_CRTC_IN_VBLANK_EVENT	0x12
 
 /** DRM_IOCTL_GET_CAP ioctl argument type */
 struct drm_get_cap {
@@ -863,7 +864,7 @@ struct drm_event_vblank {
 	__u32 tv_sec;
 	__u32 tv_usec;
 	__u32 sequence;
-	__u32 reserved;
+	__u32 crtc_id; /* 0 on older kernels that do not support this */
 };
 
 /* typedef area */
-- 
2.41.0