diff --git a/spec/index.bs b/spec/index.bs
index 3dd76940e4..be5f9659ab 100644
--- a/spec/index.bs
+++ b/spec/index.bs
@@ -6816,10 +6816,12 @@ Issue: Because timestamp query provides high-resolution GPU timestamp, we need t
 interface GPUCanvasContext {
     GPUSwapChain configureSwapChain(GPUSwapChainDescriptor descriptor);
 
-    Promise<GPUTextureFormat> getSwapChainPreferredFormat(GPUDevice device);
+    GPUTextureFormat getSwapChainPreferredFormat(GPUAdapter adapter);
 };
 </script>
 
+{{GPUCanvasContext}} has the following methods:
+
 <dl dfn-type=method dfn-for=GPUCanvasContext>
     : <dfn>configureSwapChain(descriptor)</dfn>
     ::
@@ -6829,19 +6831,28 @@ interface GPUCanvasContext {
         textures it has produced.
 
         <div algorithm="GPUCanvasContext.configureSwapChain">
-            **Called on:** {{GPUCanvasContext}} this.
+            **Called on:** {{GPUCanvasContext}} |this|.
 
             **Arguments:**
             <pre class=argumentdef for="GPUCanvasContext/configureSwapChain(descriptor)">
-                descriptor: Description of the {{GPUSwapChain}} to configure.
+                |descriptor|: Description of the {{GPUSwapChain}} to configure.
             </pre>
 
             **Returns:** {{GPUSwapChain}}
 
-            Issue: Describe {{GPUCanvasContext/configureSwapChain()}} algorithm steps.
+            1. Issue the following steps on the [=Device timeline=] of |this|:
+                <div class=device-timeline>
+                    1. If any of the following conditions are unsatisfied, generate a validation error and stop.
+                        <div class=validusage>
+                            - |descriptor|.{{GPUSwapChainDescriptor/device}} is a [=valid=] {{GPUDevice}}.
+                            - [=Supported swap chain formats=] [=set/contains=] |descriptor|.{{GPUSwapChainDescriptor/format}}.
+                        </div>
+
+                    Issue: Describe remaining {{GPUCanvasContext/configureSwapChain()}} algorithm steps.
+                </div>
         </div>
 
-    : <dfn>getSwapChainPreferredFormat(device)</dfn>
+    : <dfn>getSwapChainPreferredFormat(adapter)</dfn>
     ::
         Returns an optimal {{GPUTextureFormat}} to use for swap chains with this context and the
         given device.
@@ -6850,16 +6861,25 @@ interface GPUCanvasContext {
             **Called on:** {{GPUCanvasContext}} this.
 
             **Arguments:**
-            <pre class=argumentdef for="GPUCanvasContext/getSwapChainPreferredFormat(device)">
-                device: Device the swap chain format should be queried for.
+            <pre class=argumentdef for="GPUCanvasContext/getSwapChainPreferredFormat(adapter)">
+                |adapter|: Adapter the swap chain format should be queried for.
             </pre>
 
-            **Returns:** {{Promise}}&lt;{{GPUTextureFormat}}&gt;
+            **Returns:** {{GPUTextureFormat}}
 
-            Issue: Describe {{GPUCanvasContext/getSwapChainPreferredFormat()}} algorithm steps.
+            <div class=content-timeline>
+                1. Return an optimal {{GPUTextureFormat}} to use when creating a {{GPUSwapChain}}
+                    with the given |adapter|. Must be one of the [=supported swap chain formats=].
+            </div>
         </div>
 </dl>
 
+The <dfn dfn>supported swap chain formats</dfn> are a [=set=] of {{GPUTextureFormat}}s that must be
+supported when specified as a {{GPUSwapChainDescriptor}}.{{GPUSwapChainDescriptor/format}} regardless
+of the given {{GPUSwapChainDescriptor}}.{{GPUSwapChainDescriptor/device}}, initially set to:
+&laquo;{{GPUTextureFormat/"bgra8unorm"}}, {{GPUTextureFormat/"bgra8unorm-srgb"}},
+{{GPUTextureFormat/"rgba8unorm"}}, {{GPUTextureFormat/"rgba8unorm-srgb"}}&raquo;.
+
 <script type=idl>
 dictionary GPUSwapChainDescriptor : GPUObjectDescriptorBase {
     required GPUDevice device;