From e2afe84c6978b40ac349b885c321a6f106cf6a32 Mon Sep 17 00:00:00 2001
From: 2sumtech <2sumtech@gmail.com>
Date: Thu, 20 Aug 2026 16:39:44 -0700
Subject: [PATCH] Fix CPU dequantize_4bit output shape for 1-D inputs

---
 bitsandbytes/backends/cpu/ops.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/bitsandbytes/backends/cpu/ops.py b/bitsandbytes/backends/cpu/ops.py
index 44fb5dceb..7774477e3 100755
--- a/bitsandbytes/backends/cpu/ops.py
+++ b/bitsandbytes/backends/cpu/ops.py
@@ -169,9 +169,10 @@ def _(
         if absmax.dtype != torch.float32:
             absmax = absmax.float()
 
-        if len(shape) == 1:
-            shape = (1, shape[0])
-
+        # The kernel views the input as a 2-D (m, n) matrix, with m == 1 for 1-D
+        # inputs. The output buffer keeps the caller-provided shape: the
+        # CUDA/default/MPS backends and the registered fake kernel all return
+        # exactly `shape`.
         m = prod(shape[:-1])
         n = shape[-1]