unstub dma_fence_chain_find_seqno() for non zero seqno

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index 96e3f7a..0591c34 100644 (file)
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: drm_linux.c,v 1.85 2022/01/14 06:52:59 jsg Exp $      */
+/*     $OpenBSD: drm_linux.c,v 1.86 2022/01/17 03:54:03 jsg Exp $      */
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -2018,10 +2018,30 @@ const struct dma_fence_ops dma_fence_array_ops = {
 int
 dma_fence_chain_find_seqno(struct dma_fence **df, uint64_t seqno)
 {
+       struct dma_fence_chain *chain;
+       struct dma_fence *fence;
+
        if (seqno == 0)
                return 0;
-       STUB();
-       return -ENOSYS;
+
+       if ((chain = to_dma_fence_chain(*df)) == NULL)
+               return -EINVAL;
+
+       fence = &chain->base;
+       if (fence->seqno < seqno)
+               return -EINVAL;
+
+       dma_fence_chain_for_each(*df, fence) {
+               if ((*df)->context != fence->context)
+                       break;
+
+               chain = to_dma_fence_chain(*df);
+               if (chain->prev_seqno < seqno)
+                       break;
+       }
+       dma_fence_put(fence);
+
+       return 0;
 }
 
 void