[src/trunk]: src/sys/external/bsd/drm2/dist/drm drm: Fix vblank locking.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b37e6d296e0c
branches:  trunk
changeset: 1028475:b37e6d296e0c
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 11:08:02 2021 +0000

description:
drm: Fix vblank locking.

diffstat:

 sys/external/bsd/drm2/dist/drm/drm_vblank.c |  13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diffs (57 lines):

diff -r e8d3f65f0ff4 -r b37e6d296e0c sys/external/bsd/drm2/dist/drm/drm_vblank.c
--- a/sys/external/bsd/drm2/dist/drm/drm_vblank.c       Sun Dec 19 11:07:55 2021 +0000
+++ b/sys/external/bsd/drm2/dist/drm/drm_vblank.c       Sun Dec 19 11:08:02 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_vblank.c,v 1.5 2021/12/19 09:52:34 riastradh Exp $ */
+/*     $NetBSD: drm_vblank.c,v 1.6 2021/12/19 11:08:02 riastradh Exp $ */
 
 /*
  * drm_irq.c IRQ and vblank support
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: drm_vblank.c,v 1.5 2021/12/19 09:52:34 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: drm_vblank.c,v 1.6 2021/12/19 11:08:02 riastradh Exp $");
 
 #include <linux/export.h>
 #include <linux/moduleparam.h>
@@ -167,6 +167,8 @@
        ktime_t t_vblank;
        int count = DRM_TIMESTAMP_MAXRETRIES;
 
+       assert_spin_locked(&dev->vbl_lock);
+
        spin_lock(&dev->vblank_time_lock);
 
        /*
@@ -218,6 +220,8 @@
        int framedur_ns = vblank->framedur_ns;
        u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
 
+       assert_spin_locked(&dev->vbl_lock);
+
        /*
         * Interrupts were disabled prior to this call, so deal with counter
         * wrap if needed.
@@ -1832,8 +1836,11 @@
         */
        spin_lock(&dev->vblank_time_lock);
 
+       spin_lock(&dev->vbl_lock);
+
        /* Vblank irq handling disabled. Nothing to do. */
        if (!vblank->enabled) {
+               spin_unlock(&dev->vbl_lock);
                spin_unlock(&dev->vblank_time_lock);
                spin_unlock_irqrestore(&dev->event_lock, irqflags);
                return false;
@@ -1858,6 +1865,8 @@
                       drm_vblank_offdelay > 0 &&
                       !atomic_read(&vblank->refcount));
 
+       spin_unlock(&dev->vbl_lock);
+
        drm_handle_vblank_events(dev, pipe);
 
        spin_unlock_irqrestore(&dev->event_lock, irqflags);