[PowerDisplay] Confirm before enabling module; log EdidId in Phase 0 (#48111)

## Summary of the Pull Request

Two crash-correlation aids for the kernel-side DDC/CI BSOD mitigated by
#47734:

1. Log EDID hardware ID (manufacturer + product code, e.g. `DELD1A8`)
during Phase 0 monitor classification, before any DDC/CI capability
fetch enters the BSOD risk window.
2. Show a confirmation dialog before turning the Power Display module on
from the Settings page, so the user understands the BSOD risk before the
first capability fetch runs.

## PR Checklist

- [ ] Closes: #xxx
- [x] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [x] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

## Detailed Description of the Pull Request / Additional comments

### 1. Phase 0 EdidId logging

`MonitorIdentity.EdidIdFromDevicePath` parses the EDID hardware ID
segment from a DevicePath of the form
``\?\DISPLAY#DELD1A8#5&abc&0&UID12345#{guid}`` and returns ``DELD1A8``.
The 3-letter PNP manufacturer code + 4-hex product code is identical for
every physical unit of the same model, so it identifies the *model*
without leaking per-unit identifiers.

`MonitorManager` logs the EdidId on the existing Phase 0 classification
line. Phase 0 uses `QueryDisplayConfig`, which reads OS-cached EDID and
cannot BSOD, so this line is guaranteed on disk before the crash-prone
Phase 2 capability fetch starts. If a machine crashes during
enumeration, the recovered log identifies every attached model
(including same-model duplicates), which makes it possible to correlate
crash reports to specific monitor models even when the user can't tell
us which monitor caused the crash.

### 2. Enable-module confirmation dialog

`PowerDisplayViewModel.IsEnabled` setter is refactored to follow the
same two-phase pattern already used by `MaxCompatibilityMode`:

- `false → true` does not commit immediately; it kicks off
`ConfirmAndEnableModuleAsync`, which awaits the existing
`DangerousFeatureWarningDialog` (resource prefix
`PowerDisplay_EnableModule`) and either commits or reverts the
ToggleSwitch via `OnPropertyChanged`.
- `true → false` commits unconditionally — we never block a user who
wants to turn the module off.
- App-startup loads via `InitializeEnabledValue()` /
`RefreshEnabledState()` assign the `_isEnabled` field directly,
bypassing the setter, so the dialog never fires on settings restore or
GPO refresh.
- GPO-configured state still short-circuits before any dialog logic.

The dialog reuses the existing `DangerousFeatureWarningDialog` injected
by `PowerDisplayPage.xaml.cs`. The 5 new `PowerDisplay_EnableModule_*`
strings explain that the BSOD is in Windows (not Power Display), that
Power Display will auto-disable itself after a detected crash, and that
the user has to re-enable + dismiss the warning each time.

## Validation Steps Performed

- Built `src/settings-ui` and `src/modules/powerdisplay` locally.
- Unit tests: added `EdidIdFromDevicePath_*` cases to
`MonitorIdentityTests`, all green.
- Settings UI manual: toggling Power Display ON now shows the warning
dialog. Pressing Cancel reverts the ToggleSwitch visually; pressing
Enable commits and the module starts. Toggling OFF does not prompt.
Restarting Settings UI with PowerDisplay enabled does not prompt.
GPO-disabled state still locks the toggle.
- Log inspection: `MonitorManager` Phase 0 log now shows `EdidId=...`
for each path before any capability fetch.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Yu Leng (from Dev Box) <yuleng@microsoft.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

src/modules/powerdisplay/PowerDisplay.Lib.UnitTests/MonitorIdentityTests.cs

@@ -120,6 +120,31 @@ public void EdidIdFromMonitorId_NewFormat_ReturnsMiddleSegment()
         Assert.AreEqual("DELD1A8", MonitorIdentity.EdidIdFromMonitorId(input));
     }
 
+    [TestMethod]
+    public void EdidIdFromMonitorId_RawDevicePathWithTrailingGuid_ReturnsMiddleSegment()
+    {
+        // The Phase 0 classification log calls EdidIdFromMonitorId with a raw
+        // QueryDisplayConfig DevicePath (still carrying the trailing "#{guid}" segment).
+        // The helper must extract the EdidId correctly for that form too.
+        var input = @"\\?\DISPLAY#DELD1A8#5&abc123&0&UID12345#{e6f07b5f-ee97-4a90-b076-33f57bf4eaa7}";
+
+        Assert.AreEqual("DELD1A8", MonitorIdentity.EdidIdFromMonitorId(input));
+    }
+
+    [TestMethod]
+    public void EdidIdFromMonitorId_SameModelMonitorsProduceSameId()
+    {
+        // Two Dell U2723QE on different ports share an EdidId but have different UIDs.
+        // Logging the EdidId identifies the model for crash correlation without leaking
+        // per-unit identifiers.
+        var portA = @"\\?\DISPLAY#DELD1A8#5&abc&0&UID111#{guid}";
+        var portB = @"\\?\DISPLAY#DELD1A8#5&xyz&0&UID222#{guid}";
+
+        Assert.AreEqual(
+            MonitorIdentity.EdidIdFromMonitorId(portA),
+            MonitorIdentity.EdidIdFromMonitorId(portB));
+    }
+
     [TestMethod]
     public void EdidIdFromMonitorId_NullEmptyOrMalformed_ReturnsEmpty()
     {

src/modules/powerdisplay/PowerDisplay.Lib/Models/MonitorIdentity.cs

@@ -94,13 +94,15 @@ public static string PnpHardwareKeyFromInstanceName(string? instanceName)
     }
 
     /// <summary>
-    /// Extract the EDID PnP identifier from a new-format <c>Monitor.Id</c>. The new format
-    /// is the DevicePath returned by <c>QueryDisplayConfig</c> with the trailing device-class
-    /// GUID suffix stripped; the EdidId sits between the leading <c>"\\?\DISPLAY#"</c> and
-    /// the next <c>#</c>.
+    /// Extract the EDID PnP identifier (3-letter PNP manufacturer + 4-hex product code,
+    /// e.g. <c>"DELD1A8"</c>) from either a new-format <c>Monitor.Id</c> or a raw
+    /// <c>QueryDisplayConfig</c> DevicePath. The EdidId sits between the leading
+    /// <c>"\\?\DISPLAY#"</c> and the next <c>#</c>, and is identical for every physical
+    /// monitor of the same model — use it for "which model" crash correlation without
+    /// leaking per-unit identifiers.
     /// </summary>
-    /// <param name="monitorId">A Monitor.Id in the new DevicePath-based format.</param>
-    /// <returns>EdidId segment (e.g. <c>"DELD1A8"</c>), or empty string if the input is not a new-format Id.</returns>
+    /// <param name="monitorId">A Monitor.Id (no trailing <c>#{guid}</c>) or a raw DevicePath (with trailing <c>#{guid}</c>).</param>
+    /// <returns>EdidId segment (e.g. <c>"DELD1A8"</c>), or empty string if the input is not a recognized form.</returns>
     public static string EdidIdFromMonitorId(string? monitorId)
     {
         if (string.IsNullOrEmpty(monitorId))

src/modules/powerdisplay/PowerDisplay/Helpers/MonitorManager.cs

@@ -204,8 +204,16 @@ private static void LogClassificationSummary(
                     : info.OutputTechnology.ToString(CultureInfo.InvariantCulture);
                 var classification = info.IsInternal ? "Internal" : "External";
 
+                // Log EdidId (manufacturer+product code from EDID) up front, before any
+                // DDC/CI capability fetch runs. QueryDisplayConfig reads OS-cached EDID and
+                // cannot BSOD, so this line is guaranteed on disk before the crash-prone
+                // Phase 2 fetch starts — recovered logs identify every attached model
+                // (and same-model duplicates) for crash correlation.
+                var edidId = MonitorIdentity.EdidIdFromMonitorId(info.DevicePath);
+                var edidIdField = string.IsNullOrEmpty(edidId) ? "?" : edidId;
+
                 Logger.LogInfo(
-                    $"  [Path {info.MonitorNumber}] {info.GdiDeviceName} / \"{info.FriendlyName}\": " +
+                    $"  [Path {info.MonitorNumber}] EdidId={edidIdField} {info.GdiDeviceName} / \"{info.FriendlyName}\": " +
                     $"OutputTechnology={techValue} → {classification}");
             }
 

src/settings-ui/Settings.UI/SettingsXAML/Views/DangerousFeatureWarningDialog.xaml

@@ -15,10 +15,18 @@
             Foreground="{ThemeResource SystemFillColorCriticalBrush}"
             TextWrapping="Wrap" />
         <TextBlock x:Name="WarningDescription" TextWrapping="Wrap" />
-        <TextBlock
-            x:Name="WarningList"
-            Margin="20,0,0,0"
-            TextWrapping="Wrap" />
+        <ItemsControl x:Name="WarningList" Margin="20,0,0,0">
+            <ItemsControl.ItemsPanel>
+                <ItemsPanelTemplate>
+                    <StackPanel Spacing="4" />
+                </ItemsPanelTemplate>
+            </ItemsControl.ItemsPanel>
+            <ItemsControl.ItemTemplate>
+                <DataTemplate x:DataType="x:String">
+                    <TextBlock Text="{x:Bind}" TextWrapping="Wrap" />
+                </DataTemplate>
+            </ItemsControl.ItemTemplate>
+        </ItemsControl>
         <TextBlock
             x:Name="WarningConfirm"
             FontWeight="SemiBold"

src/settings-ui/Settings.UI/SettingsXAML/Views/DangerousFeatureWarningDialog.xaml.cs

@@ -2,30 +2,62 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Collections.Generic;
 using Microsoft.PowerToys.Settings.UI.Helpers;
 using Microsoft.UI.Xaml.Controls;
+using Microsoft.Windows.ApplicationModel.Resources;
 
 namespace Microsoft.PowerToys.Settings.UI.Views
 {
     /// <summary>
     /// Confirmation dialog shown when the user enables a feature that can damage the
     /// hardware or otherwise leave it in a non-recoverable state. The caller supplies a
-    /// resource key prefix; the dialog loads "{prefix}_WarningTitle/Header/Description/List/Confirm".
+    /// resource key prefix; the dialog loads
+    /// "{prefix}_WarningTitle/Header/Description/WarningList_Item{N}/Confirm".
+    /// Bullets are prepended in code so translators only see the body text; the
+    /// item loop probes <c>_WarningList_Item1</c>, <c>_Item2</c>, ... until a missing
+    /// key is hit, so adding a 4th bullet only requires a new resw entry.
     /// </summary>
     public sealed partial class DangerousFeatureWarningDialog : ContentDialog
     {
+        // Visual decorations are applied in code so translators only see body text.
+        private const string WarningHeaderPrefix = "⚠️ ";
+        private const string BulletPrefix = "• ";
+
+        // Hard cap on bullet probes; a real dialog never approaches this.
+        private const int MaxBulletItems = 10;
+
+        // Direct ResourceMap handle so the bullet loop can probe for missing keys with
+        // TryGetValue (returns null) instead of ResourceLoader.GetString (throws
+        // "NamedResource Not Found").
+        private static readonly ResourceMap ResourceMap =
+            new ResourceManager("PowerToys.Settings.pri").MainResourceMap.GetSubtree("Resources");
+
         public DangerousFeatureWarningDialog(string resourceKeyPrefix)
         {
             InitializeComponent();
 
             var loader = ResourceLoaderInstance.ResourceLoader;
             Title = loader.GetString($"{resourceKeyPrefix}_WarningTitle");
-            WarningHeader.Text = loader.GetString($"{resourceKeyPrefix}_WarningHeader");
+            WarningHeader.Text = WarningHeaderPrefix + loader.GetString($"{resourceKeyPrefix}_WarningHeader");
             WarningDescription.Text = loader.GetString($"{resourceKeyPrefix}_WarningDescription");
-            WarningList.Text = loader.GetString($"{resourceKeyPrefix}_WarningList");
             WarningConfirm.Text = loader.GetString($"{resourceKeyPrefix}_WarningConfirm");
             PrimaryButtonText = loader.GetString("PowerDisplay_Dialog_Enable");
             CloseButtonText = loader.GetString("PowerDisplay_Dialog_Cancel");
+
+            var items = new List<string>();
+            for (int i = 1; i <= MaxBulletItems; i++)
+            {
+                var candidate = ResourceMap.TryGetValue($"{resourceKeyPrefix}_WarningList_Item{i}");
+                if (candidate == null || string.IsNullOrEmpty(candidate.ValueAsString))
+                {
+                    break;
+                }
+
+                items.Add(BulletPrefix + candidate.ValueAsString);
+            }
+
+            WarningList.ItemsSource = items;
         }
     }
 }

src/settings-ui/Settings.UI/Strings/en-us/Resources.resw

@@ -5579,15 +5579,16 @@ The break timer font matches the text font.</value>
     <value>Confirm Color Temperature Change</value>
   </data>
   <data name="PowerDisplay_ColorTemperature_WarningHeader" xml:space="preserve">
-    <value>⚠️ Warning: This is a potentially dangerous operation!</value>
+    <value>Warning: This is a potentially dangerous operation!</value>
   </data>
   <data name="PowerDisplay_ColorTemperature_WarningDescription" xml:space="preserve">
     <value>Changing the color temperature setting may cause unpredictable results including:</value>
   </data>
-  <data name="PowerDisplay_ColorTemperature_WarningList" xml:space="preserve">
-    <value>• Incorrect display colors
-• Display malfunction
-• Settings that cannot be reverted</value>
+  <data name="PowerDisplay_ColorTemperature_WarningList_Item1" xml:space="preserve">
+    <value>Incorrect display colors or other display malfunction</value>
+  </data>
+  <data name="PowerDisplay_ColorTemperature_WarningList_Item2" xml:space="preserve">
+    <value>Settings that cannot be reverted</value>
   </data>
   <data name="PowerDisplay_ColorTemperature_WarningConfirm" xml:space="preserve">
     <value>Do you want to enable color temperature control for this monitor?</value>
@@ -5608,15 +5609,16 @@ The break timer font matches the text font.</value>
     <value>Confirm power state control</value>
   </data>
   <data name="PowerDisplay_PowerState_WarningHeader" xml:space="preserve">
-    <value>⚠️ Warning: This action may be unsafe.</value>
+    <value>Warning: This action may be unsafe.</value>
   </data>
   <data name="PowerDisplay_PowerState_WarningDescription" xml:space="preserve">
     <value>Enabling power state control may lead to unexpected behavior, including:</value>
   </data>
-  <data name="PowerDisplay_PowerState_WarningList" xml:space="preserve">
-    <value>• Monitor may enter standby and not wake via software.
-• You may need to press the monitor’s power button or reconnect the cable to recover.
-• Some monitors may not restore the previous state correctly.</value>
+  <data name="PowerDisplay_PowerState_WarningList_Item1" xml:space="preserve">
+    <value>Monitor may enter standby and not wake via software — recovery may require the physical power button or reseating the cable.</value>
+  </data>
+  <data name="PowerDisplay_PowerState_WarningList_Item2" xml:space="preserve">
+    <value>Some monitors may not restore the previous state correctly.</value>
   </data>
   <data name="PowerDisplay_PowerState_WarningConfirm" xml:space="preserve">
     <value>Enable power state control for this monitor?</value>
@@ -5625,15 +5627,19 @@ The break timer font matches the text font.</value>
     <value>Confirm input source control</value>
   </data>
   <data name="PowerDisplay_InputSource_WarningHeader" xml:space="preserve">
-    <value>⚠️ Warning: This action may be unsafe.</value>
+    <value>Warning: This action may be unsafe.</value>
   </data>
   <data name="PowerDisplay_InputSource_WarningDescription" xml:space="preserve">
     <value>Switching input sources may cause unintended results, including:</value>
   </data>
-  <data name="PowerDisplay_InputSource_WarningList" xml:space="preserve">
-    <value>• Screen may go black if the selected input has no signal.
-• Software control may be lost until you switch back using the monitor’s physical buttons.
-• Some monitors may not reliably expose all input sources.</value>
+  <data name="PowerDisplay_InputSource_WarningList_Item1" xml:space="preserve">
+    <value>Screen may go black if the selected input has no signal.</value>
+  </data>
+  <data name="PowerDisplay_InputSource_WarningList_Item2" xml:space="preserve">
+    <value>Software control may be lost until you switch back using the monitor’s physical buttons.</value>
+  </data>
+  <data name="PowerDisplay_InputSource_WarningList_Item3" xml:space="preserve">
+    <value>Some monitors may not reliably expose all input sources.</value>
   </data>
   <data name="PowerDisplay_InputSource_WarningConfirm" xml:space="preserve">
     <value>Enable input source control for this monitor?</value>
@@ -5642,19 +5648,41 @@ The break timer font matches the text font.</value>
     <value>Confirm maximum compatibility mode</value>
   </data>
   <data name="PowerDisplay_MaxCompatibility_WarningHeader" xml:space="preserve">
-    <value>⚠️ Warning: This may cause unstable monitor behavior.</value>
+    <value>Warning: This may cause unstable monitor behavior.</value>
   </data>
   <data name="PowerDisplay_MaxCompatibility_WarningDescription" xml:space="preserve">
     <value>Maximum compatibility mode bypasses your monitor's capabilities string and sends a probe for every supported VCP feature. Some monitors do not handle this well, which may cause:</value>
   </data>
-  <data name="PowerDisplay_MaxCompatibility_WarningList" xml:space="preserve">
-    <value>• The screen may go black or briefly lose signal during discovery.
-• The monitor may respond unpredictably, including unwanted changes to brightness, contrast, or input source.
-• The monitor may stop responding to DDC/CI until it is power-cycled.</value>
+  <data name="PowerDisplay_MaxCompatibility_WarningList_Item1" xml:space="preserve">
+    <value>The screen may go black or briefly lose signal during discovery.</value>
+  </data>
+  <data name="PowerDisplay_MaxCompatibility_WarningList_Item2" xml:space="preserve">
+    <value>The monitor may respond unpredictably, including unwanted changes to brightness, contrast, or input source.</value>
+  </data>
+  <data name="PowerDisplay_MaxCompatibility_WarningList_Item3" xml:space="preserve">
+    <value>The monitor may stop responding to DDC/CI until it is power-cycled.</value>
   </data>
   <data name="PowerDisplay_MaxCompatibility_WarningConfirm" xml:space="preserve">
     <value>Only enable this if a monitor is missing from Power Display and you fully understand the side effects listed above. Continue?</value>
   </data>
+  <data name="PowerDisplay_EnableModule_WarningTitle" xml:space="preserve">
+    <value>Enable Power Display?</value>
+  </data>
+  <data name="PowerDisplay_EnableModule_WarningHeader" xml:space="preserve">
+    <value>Warning: This may cause a system crash on a small number of monitors.</value>
+  </data>
+  <data name="PowerDisplay_EnableModule_WarningDescription" xml:space="preserve">
+    <value>Power Display reads each connected monitor's DDC/CI capabilities at startup. On a small number of monitors with malformed capability strings, this read has been observed to trigger a kernel-side bug that causes Windows to bug-check (BSOD). The underlying issue is in Windows, not in Power Display, but the read is what surfaces it. Possible effects:</value>
+  </data>
+  <data name="PowerDisplay_EnableModule_WarningList_Item1" xml:space="preserve">
+    <value>On affected monitors, the system may crash and restart.</value>
+  </data>
+  <data name="PowerDisplay_EnableModule_WarningList_Item2" xml:space="preserve">
+    <value>If a crash is detected, Power Display will auto-disable itself on next launch; you'll need to re-enable the module and dismiss the warning on the settings page each time.</value>
+  </data>
+  <data name="PowerDisplay_EnableModule_WarningConfirm" xml:space="preserve">
+    <value>Only enable Power Display if you accept the risk above. Continue?</value>
+  </data>
   <data name="PowerDisplay_Dialog_Enable" xml:space="preserve">
     <value>Enable</value>
   </data>