diff --git a/sumpy/p2p.py b/sumpy/p2p.py
index 040f579e3c157519887a497e5e0a43901b132a49..381918462fd6f2717f9ab0475b9d75c76e5382d4 100644
--- a/sumpy/p2p.py
+++ b/sumpy/p2p.py
@@ -492,6 +492,8 @@ class P2PFromCSR(P2PBase):
                 "{[itgt]: itgt_start <= itgt < itgt_end}",
             ]
 
+        # There are two algorithms here because pocl-pthread 1.9 miscompiles
+        # the "gpu" kernel with prefetching.
         if gpu:
             instructions = (self.get_kernel_scaling_assignments()
               + ["""