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Refactor DDC/CI monitor discovery and control logic

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- Split monitor discovery into three clear phases for readability and performance
- Introduce CandidateMonitor record for better data handling
- Fetch DDC/CI capabilities in parallel to speed up enumeration
- Filter out NULL physical monitor handles and retry up to 3 times
- Refactor color temperature and input source access to use generic VCP feature methods
- Add discrete VCP value validation for safer set operations
- Move input source verification to a dedicated method
- Improve error handling and logging throughout
- Remove obsolete tuple code and update documentation for maintainability
This commit is contained in:
Yu Leng
2025-12-10 06:21:50 +08:00
parent b004fe1445
commit 0bc59e7101
2 changed files with 367 additions and 310 deletions
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654
src/modules/powerdisplay/PowerDisplay.Lib/Drivers/DDC/DdcCiController.cs
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@@ -29,6 +29,24 @@ namespace PowerDisplay.Common.Drivers.DDC
/// </summary>
public partial class DdcCiController : IMonitorController, IDisposable
{
/// <summary>
/// Represents a candidate monitor discovered during Phase 1 of monitor enumeration.
/// This record replaces the long tuple for better readability and maintainability.
/// </summary>
/// <param name="Handle">Physical monitor handle for DDC/CI communication</param>
/// <param name="DeviceKey">Stable device key for handle reuse across discoveries</param>
/// <param name="PhysicalMonitor">Native physical monitor structure with description</param>
/// <param name="AdapterName">Display adapter name (e.g., "\\.\DISPLAY1")</param>
/// <param name="Index">Index of this monitor on its adapter</param>
/// <param name="MatchedDevice">Optional matched DisplayDeviceInfo with EDID data</param>
private readonly record struct CandidateMonitor(
IntPtr Handle,
string DeviceKey,
PHYSICAL_MONITOR PhysicalMonitor,
string AdapterName,
int Index,
DisplayDeviceInfo? MatchedDevice);
/// <summary>
/// Delay between retry attempts for DDC/CI operations (in milliseconds)
/// </summary>
@@ -118,28 +136,7 @@ namespace PowerDisplay.Common.Drivers.DDC
public async Task<BrightnessInfo> GetColorTemperatureAsync(Monitor monitor, CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(monitor);
return await Task.Run(
() =>
{
if (monitor.Handle == IntPtr.Zero)
{
Logger.LogDebug($"[{monitor.Id}] Invalid handle for color temperature read");
return BrightnessInfo.Invalid;
}
// Try VCP code 0x14 (Select Color Preset)
if (DdcCiNative.TryGetVCPFeature(monitor.Handle, VcpCodeSelectColorPreset, out uint current, out uint max))
{
var presetName = VcpValueNames.GetFormattedName(0x14, (int)current);
Logger.LogDebug($"[{monitor.Id}] Color temperature via 0x14: {presetName}");
return new BrightnessInfo((int)current, 0, (int)max);
}
Logger.LogWarning($"[{monitor.Id}] Failed to read color temperature (0x14 not supported)");
return BrightnessInfo.Invalid;
},
cancellationToken);
return await GetVcpFeatureAsync(monitor, VcpCodeSelectColorPreset, "Color temperature", cancellationToken);
}
/// <summary>
@@ -162,21 +159,15 @@ namespace PowerDisplay.Common.Drivers.DDC
try
{
// Validate value is in supported list if capabilities available
var capabilities = monitor.VcpCapabilitiesInfo;
if (capabilities != null && capabilities.SupportsVcpCode(0x14))
// Validate value is in supported list
var validationError = ValidateDiscreteVcpValue(monitor, VcpCodeSelectColorPreset, colorTemperature, "Color preset");
if (validationError != null)
{
var supportedValues = capabilities.GetSupportedValues(0x14);
if (supportedValues?.Count > 0 && !supportedValues.Contains(colorTemperature))
{
var supportedList = string.Join(", ", supportedValues.Select(v => $"0x{v:X2}"));
Logger.LogWarning($"[{monitor.Id}] Color preset 0x{colorTemperature:X2} not in supported list: [{supportedList}]");
return MonitorOperationResult.Failure($"Color preset 0x{colorTemperature:X2} not supported by monitor");
}
return validationError.Value;
}
// Set VCP 0x14 value
var presetName = VcpValueNames.GetFormattedName(0x14, colorTemperature);
var presetName = VcpValueNames.GetFormattedName(VcpCodeSelectColorPreset, colorTemperature);
if (DdcCiNative.TrySetVCPFeature(monitor.Handle, VcpCodeSelectColorPreset, (uint)colorTemperature))
{
Logger.LogInfo($"[{monitor.Id}] Set color temperature to {presetName} via 0x14");
@@ -185,7 +176,7 @@ namespace PowerDisplay.Common.Drivers.DDC
var lastError = GetLastError();
Logger.LogError($"[{monitor.Id}] Failed to set color temperature, error: {lastError}");
return MonitorOperationResult.Failure($"Failed to set color temperature via DDC/CI", (int)lastError);
return MonitorOperationResult.Failure("Failed to set color temperature via DDC/CI", (int)lastError);
}
catch (Exception ex)
{
@@ -203,28 +194,7 @@ namespace PowerDisplay.Common.Drivers.DDC
public async Task<BrightnessInfo> GetInputSourceAsync(Monitor monitor, CancellationToken cancellationToken = default)
{
ArgumentNullException.ThrowIfNull(monitor);
return await Task.Run(
() =>
{
if (monitor.Handle == IntPtr.Zero)
{
Logger.LogDebug($"[{monitor.Id}] Invalid handle for input source read");
return BrightnessInfo.Invalid;
}
// Try VCP code 0x60 (Input Source)
if (DdcCiNative.TryGetVCPFeature(monitor.Handle, VcpCodeInputSource, out uint current, out uint max))
{
var sourceName = VcpValueNames.GetFormattedName(0x60, (int)current);
Logger.LogDebug($"[{monitor.Id}] Input source via 0x60: {sourceName}");
return new BrightnessInfo((int)current, 0, (int)max);
}
Logger.LogWarning($"[{monitor.Id}] Failed to read input source (0x60 not supported)");
return BrightnessInfo.Invalid;
},
cancellationToken);
return await GetVcpFeatureAsync(monitor, VcpCodeInputSource, "Input source", cancellationToken);
}
/// <summary>
@@ -247,43 +217,21 @@ namespace PowerDisplay.Common.Drivers.DDC
try
{
// Validate value is in supported list if capabilities available
var capabilities = monitor.VcpCapabilitiesInfo;
if (capabilities != null && capabilities.SupportsVcpCode(0x60))
// Validate value is in supported list
var validationError = ValidateDiscreteVcpValue(monitor, VcpCodeInputSource, inputSource, "Input source");
if (validationError != null)
{
var supportedValues = capabilities.GetSupportedValues(0x60);
if (supportedValues?.Count > 0 && !supportedValues.Contains(inputSource))
{
var supportedList = string.Join(", ", supportedValues.Select(v => $"0x{v:X2}"));
Logger.LogWarning($"[{monitor.Id}] Input source 0x{inputSource:X2} not in supported list: [{supportedList}]");
return MonitorOperationResult.Failure($"Input source 0x{inputSource:X2} not supported by monitor");
}
return validationError.Value;
}
// Set VCP 0x60 value
var sourceName = VcpValueNames.GetFormattedName(0x60, inputSource);
var sourceName = VcpValueNames.GetFormattedName(VcpCodeInputSource, inputSource);
if (DdcCiNative.TrySetVCPFeature(monitor.Handle, VcpCodeInputSource, (uint)inputSource))
{
Logger.LogInfo($"[{monitor.Id}] Set input source to {sourceName} via 0x60");
// Verify the change by reading back the value after a short delay
await Task.Delay(100, cancellationToken).ConfigureAwait(false);
if (DdcCiNative.TryGetVCPFeature(monitor.Handle, VcpCodeInputSource, out uint verifyValue, out uint _))
{
var verifyName = VcpValueNames.GetFormattedName(0x60, (int)verifyValue);
if (verifyValue == (uint)inputSource)
{
Logger.LogDebug($"[{monitor.Id}] Input source verified: {verifyName} (0x{verifyValue:X2})");
}
else
{
Logger.LogWarning($"[{monitor.Id}] Input source verification mismatch! Expected 0x{inputSource:X2}, got {verifyName} (0x{verifyValue:X2}). Monitor may have refused to switch (no signal on target port?)");
}
}
else
{
Logger.LogWarning($"[{monitor.Id}] Could not verify input source change");
}
await VerifyInputSourceChangeAsync(monitor, inputSource, cancellationToken);
// Update the monitor model with the new value
monitor.CurrentInputSource = inputSource;
@@ -293,7 +241,7 @@ namespace PowerDisplay.Common.Drivers.DDC
var lastError = GetLastError();
Logger.LogError($"[{monitor.Id}] Failed to set input source, error: {lastError}");
return MonitorOperationResult.Failure($"Failed to set input source via DDC/CI", (int)lastError);
return MonitorOperationResult.Failure("Failed to set input source via DDC/CI", (int)lastError);
}
catch (Exception ex)
{
@@ -304,6 +252,32 @@ namespace PowerDisplay.Common.Drivers.DDC
cancellationToken);
}
/// <summary>
/// Verify input source change by reading back the value after a short delay.
/// Logs warning if verification fails or value doesn't match.
/// </summary>
private static async Task VerifyInputSourceChangeAsync(Monitor monitor, int expectedValue, CancellationToken cancellationToken)
{
await Task.Delay(100, cancellationToken).ConfigureAwait(false);
if (DdcCiNative.TryGetVCPFeature(monitor.Handle, VcpCodeInputSource, out uint verifyValue, out uint _))
{
var verifyName = VcpValueNames.GetFormattedName(VcpCodeInputSource, (int)verifyValue);
if (verifyValue == (uint)expectedValue)
{
Logger.LogDebug($"[{monitor.Id}] Input source verified: {verifyName} (0x{verifyValue:X2})");
}
else
{
Logger.LogWarning($"[{monitor.Id}] Input source verification mismatch! Expected 0x{expectedValue:X2}, got {verifyName} (0x{verifyValue:X2}). Monitor may have refused to switch (no signal on target port?)");
}
}
else
{
Logger.LogWarning($"[{monitor.Id}] Could not verify input source change");
}
}
/// <summary>
/// Get monitor capabilities string with retry logic.
/// Uses cached CapabilitiesRaw if available to avoid slow I2C operations.
@@ -396,179 +370,242 @@ namespace PowerDisplay.Common.Drivers.DDC
}
/// <summary>
/// Discover supported monitors
/// Discover supported monitors using a three-phase approach:
/// Phase 1: Enumerate and collect candidate monitors with their handles
/// Phase 2: Fetch DDC/CI capabilities in parallel (slow I2C operations)
/// Phase 3: Create Monitor objects for valid DDC/CI monitors
/// </summary>
public async Task<IEnumerable<Monitor>> DiscoverMonitorsAsync(CancellationToken cancellationToken = default)
{
return await Task.Run(
async () =>
{
var monitors = new List<Monitor>();
var newHandleMap = new Dictionary<string, IntPtr>();
try
{
// Get all display devices with stable device IDs
var displayDevices = DdcCiNative.GetAllDisplayDevices();
// Also get hardware info for friendly names
var monitorDisplayInfo = DdcCiNative.GetAllMonitorDisplayInfo();
// Enumerate all monitors
var monitorHandles = new List<IntPtr>();
bool EnumProc(IntPtr hMonitor, IntPtr hdcMonitor, IntPtr lprcMonitor, IntPtr dwData)
try
{
monitorHandles.Add(hMonitor);
return true;
// Pre-fetch display information
var displayDevices = DdcCiNative.GetAllDisplayDevices();
var monitorDisplayInfo = DdcCiNative.GetAllMonitorDisplayInfo();
// Pre-group devices by adapter for O(1) lookup instead of O(n) per monitor
var devicesByAdapter = displayDevices
.GroupBy(d => d.AdapterName)
.ToDictionary(g => g.Key, g => g.ToList());
// Phase 1: Collect candidate monitors
var monitorHandles = EnumerateMonitorHandles();
if (monitorHandles.Count == 0)
{
return Enumerable.Empty<Monitor>();
}
var candidateMonitors = await CollectCandidateMonitorsAsync(
monitorHandles, devicesByAdapter, cancellationToken);
if (candidateMonitors.Count == 0)
{
return Enumerable.Empty<Monitor>();
}
// Phase 2: Fetch capabilities in parallel
var fetchResults = await FetchCapabilitiesInParallelAsync(
candidateMonitors, cancellationToken);
// Phase 3: Create monitor objects
return CreateValidMonitors(fetchResults, monitorDisplayInfo);
}
bool enumResult = EnumDisplayMonitors(IntPtr.Zero, IntPtr.Zero, EnumProc, IntPtr.Zero);
if (!enumResult)
catch (Exception ex)
{
Logger.LogWarning($"DDC: EnumDisplayMonitors failed");
return monitors;
Logger.LogError($"DDC: DiscoverMonitorsAsync exception: {ex.Message}\nStack: {ex.StackTrace}");
return Enumerable.Empty<Monitor>();
}
// Phase 1: Collect all candidate monitors with their handles
var candidateMonitors = new List<(IntPtr Handle, string DeviceKey, PHYSICAL_MONITOR PhysicalMonitor, string AdapterName, int Index, DisplayDeviceInfo? MatchedDevice)>();
foreach (var hMonitor in monitorHandles)
{
var adapterName = _discoveryHelper.GetMonitorDeviceId(hMonitor);
if (string.IsNullOrEmpty(adapterName))
{
continue;
}
// Get physical monitors with retry logic for NULL handle workaround
var physicalMonitors = await GetPhysicalMonitorsWithRetryAsync(hMonitor, cancellationToken);
if (physicalMonitors == null || physicalMonitors.Length == 0)
{
Logger.LogWarning($"DDC: Failed to get physical monitors for hMonitor 0x{hMonitor:X} after retries");
continue;
}
// Match physical monitors with DisplayDeviceInfo
for (int i = 0; i < physicalMonitors.Length; i++)
{
var physicalMonitor = physicalMonitors[i];
if (physicalMonitor.HPhysicalMonitor == IntPtr.Zero)
{
continue;
}
// Find matching DisplayDeviceInfo for this physical monitor
DisplayDeviceInfo? matchedDevice = null;
int foundCount = 0;
foreach (var displayDevice in displayDevices)
{
if (displayDevice.AdapterName == adapterName)
{
if (foundCount == i)
{
matchedDevice = displayDevice;
break;
}
foundCount++;
}
}
// Determine device key for handle reuse logic
string deviceKey = matchedDevice?.DeviceKey ?? $"{adapterName}_{i}";
// Use HandleManager to reuse or create handle
var (handleToUse, _) = _handleManager.ReuseOrCreateHandle(deviceKey, physicalMonitor.HPhysicalMonitor);
// Update physical monitor handle
var monitorToCreate = physicalMonitor;
monitorToCreate.HPhysicalMonitor = handleToUse;
candidateMonitors.Add((handleToUse, deviceKey, monitorToCreate, adapterName, i, matchedDevice));
}
}
// Phase 2: Fetch capabilities in PARALLEL for all candidate monitors
// This is the slow I2C operation (~4s per monitor), but parallelization
// significantly reduces total time when multiple monitors are connected.
// Results are cached regardless of success/failure.
Logger.LogInfo($"DDC: Phase 2 - Fetching capabilities for {candidateMonitors.Count} monitors in parallel");
var fetchTasks = candidateMonitors.Select(candidate =>
Task.Run(
() =>
{
var capabilitiesResult = DdcCiNative.FetchCapabilities(candidate.Handle);
return (Candidate: candidate, CapabilitiesResult: capabilitiesResult);
},
cancellationToken));
var fetchResults = await Task.WhenAll(fetchTasks);
Logger.LogInfo($"DDC: Phase 2 completed - Got results for {fetchResults.Length} monitors");
// Phase 3: Create monitor objects for valid DDC/CI monitors
// A monitor is valid for DDC if it has capabilities with brightness support
foreach (var result in fetchResults)
{
// Skip monitors that don't support DDC/CI brightness control
if (!result.CapabilitiesResult.IsValid)
{
Logger.LogDebug($"DDC: Handle 0x{result.Candidate.Handle:X} - No DDC/CI brightness support, skipping");
continue;
}
var monitor = _discoveryHelper.CreateMonitorFromPhysical(
result.Candidate.PhysicalMonitor,
result.Candidate.AdapterName,
result.Candidate.Index,
monitorDisplayInfo,
result.Candidate.MatchedDevice);
if (monitor != null)
{
// Attach cached capabilities data - this is the key optimization!
// By caching here, we avoid re-fetching during InitializeMonitorCapabilitiesAsync
if (!string.IsNullOrEmpty(result.CapabilitiesResult.CapabilitiesString))
{
monitor.CapabilitiesRaw = result.CapabilitiesResult.CapabilitiesString;
}
if (result.CapabilitiesResult.VcpCapabilitiesInfo != null)
{
monitor.VcpCapabilitiesInfo = result.CapabilitiesResult.VcpCapabilitiesInfo;
}
monitors.Add(monitor);
newHandleMap[monitor.DeviceKey] = result.Candidate.Handle;
Logger.LogInfo($"DDC: Added monitor {monitor.Id} with {monitor.VcpCapabilitiesInfo?.SupportedVcpCodes.Count ?? 0} VCP codes");
}
}
// Update handle manager with new mapping
_handleManager.UpdateHandleMap(newHandleMap);
}
catch (Exception ex)
{
Logger.LogError($"DDC: DiscoverMonitorsAsync exception: {ex.Message}\nStack: {ex.StackTrace}");
}
return monitors;
},
cancellationToken);
}
/// <summary>
/// Get physical monitors with retry logic to handle Windows API occasionally returning NULL handles
/// Enumerate all logical monitor handles using Win32 API.
/// </summary>
private List<IntPtr> EnumerateMonitorHandles()
{
var handles = new List<IntPtr>();
bool EnumProc(IntPtr hMonitor, IntPtr hdcMonitor, IntPtr lprcMonitor, IntPtr dwData)
{
handles.Add(hMonitor);
return true;
}
if (!EnumDisplayMonitors(IntPtr.Zero, IntPtr.Zero, EnumProc, IntPtr.Zero))
{
Logger.LogWarning("DDC: EnumDisplayMonitors failed");
}
return handles;
}
/// <summary>
/// Phase 1: Collect all candidate monitors with their physical handles.
/// Uses pre-grouped device lookup for better performance.
/// </summary>
private async Task<List<CandidateMonitor>> CollectCandidateMonitorsAsync(
List<IntPtr> monitorHandles,
Dictionary<string, List<DisplayDeviceInfo>> devicesByAdapter,
CancellationToken cancellationToken)
{
var candidates = new List<CandidateMonitor>();
foreach (var hMonitor in monitorHandles)
{
var adapterName = _discoveryHelper.GetMonitorDeviceId(hMonitor);
if (string.IsNullOrEmpty(adapterName))
{
continue;
}
var physicalMonitors = await GetPhysicalMonitorsWithRetryAsync(hMonitor, cancellationToken);
if (physicalMonitors == null || physicalMonitors.Length == 0)
{
Logger.LogWarning($"DDC: Failed to get physical monitors for hMonitor 0x{hMonitor:X} after retries");
continue;
}
// Get devices for this adapter (O(1) lookup)
var adapterDevices = devicesByAdapter.TryGetValue(adapterName, out var devices)
? devices
: null;
candidates.AddRange(
CreateCandidatesFromPhysicalMonitors(physicalMonitors, adapterName, adapterDevices));
}
return candidates;
}
/// <summary>
/// Create candidate monitors from physical monitor array.
/// Handles device matching and handle reuse.
/// Note: NULL handles are already filtered out by GetPhysicalMonitors.
/// </summary>
private IEnumerable<CandidateMonitor> CreateCandidatesFromPhysicalMonitors(
PHYSICAL_MONITOR[] physicalMonitors,
string adapterName,
List<DisplayDeviceInfo>? adapterDevices)
{
for (int i = 0; i < physicalMonitors.Length; i++)
{
var physicalMonitor = physicalMonitors[i];
// O(1) lookup: devices are already filtered by adapter
var matchedDevice = adapterDevices != null && i < adapterDevices.Count
? adapterDevices[i]
: null;
var deviceKey = matchedDevice?.DeviceKey ?? $"{adapterName}_{i}";
var (handleToUse, _) = _handleManager.ReuseOrCreateHandle(deviceKey, physicalMonitor.HPhysicalMonitor);
var monitorToCreate = physicalMonitor;
monitorToCreate.HPhysicalMonitor = handleToUse;
yield return new CandidateMonitor(
handleToUse,
deviceKey,
monitorToCreate,
adapterName,
i,
matchedDevice);
}
}
/// <summary>
/// Phase 2: Fetch DDC/CI capabilities in parallel for all candidate monitors.
/// This is the slow I2C operation (~4s per monitor), but parallelization
/// significantly reduces total time when multiple monitors are connected.
/// </summary>
private async Task<(CandidateMonitor Candidate, DdcCiValidationResult Result)[]> FetchCapabilitiesInParallelAsync(
List<CandidateMonitor> candidates,
CancellationToken cancellationToken)
{
Logger.LogInfo($"DDC: Phase 2 - Fetching capabilities for {candidates.Count} monitors in parallel");
var tasks = candidates.Select(candidate =>
Task.Run(
() => (Candidate: candidate, Result: DdcCiNative.FetchCapabilities(candidate.Handle)),
cancellationToken));
var results = await Task.WhenAll(tasks);
Logger.LogInfo($"DDC: Phase 2 completed - Got results for {results.Length} monitors");
return results;
}
/// <summary>
/// Phase 3: Create Monitor objects for valid DDC/CI monitors.
/// A monitor is valid if it has capabilities with brightness support.
/// </summary>
private List<Monitor> CreateValidMonitors(
(CandidateMonitor Candidate, DdcCiValidationResult Result)[] fetchResults,
Dictionary<string, MonitorDisplayInfo> monitorDisplayInfo)
{
var monitors = new List<Monitor>();
var newHandleMap = new Dictionary<string, IntPtr>();
foreach (var (candidate, capResult) in fetchResults)
{
if (!capResult.IsValid)
{
Logger.LogDebug($"DDC: Handle 0x{candidate.Handle:X} - No DDC/CI brightness support, skipping");
continue;
}
var monitor = _discoveryHelper.CreateMonitorFromPhysical(
candidate.PhysicalMonitor,
candidate.AdapterName,
candidate.Index,
monitorDisplayInfo,
candidate.MatchedDevice);
if (monitor == null)
{
continue;
}
// Attach cached capabilities data to avoid re-fetching
AttachCapabilitiesToMonitor(monitor, capResult);
monitors.Add(monitor);
newHandleMap[monitor.DeviceKey] = candidate.Handle;
Logger.LogInfo($"DDC: Added monitor {monitor.Id} with {monitor.VcpCapabilitiesInfo?.SupportedVcpCodes.Count ?? 0} VCP codes");
}
_handleManager.UpdateHandleMap(newHandleMap);
return monitors;
}
/// <summary>
/// Attach cached capabilities data to monitor object.
/// This is the key optimization - avoids re-fetching during InitializeMonitorCapabilitiesAsync.
/// </summary>
private static void AttachCapabilitiesToMonitor(Monitor monitor, DdcCiValidationResult capResult)
{
if (!string.IsNullOrEmpty(capResult.CapabilitiesString))
{
monitor.CapabilitiesRaw = capResult.CapabilitiesString;
}
if (capResult.VcpCapabilitiesInfo != null)
{
monitor.VcpCapabilitiesInfo = capResult.VcpCapabilitiesInfo;
}
}
/// <summary>
/// Get physical monitors with retry logic to handle Windows API occasionally returning NULL handles.
/// NULL handles are automatically filtered out by GetPhysicalMonitors; retry if any were filtered.
/// </summary>
/// <param name="hMonitor">Handle to the monitor</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>Array of physical monitors, or null if failed after retries</returns>
/// <returns>Array of valid physical monitors, or null if failed after retries</returns>
private async Task<PHYSICAL_MONITOR[]?> GetPhysicalMonitorsWithRetryAsync(
IntPtr hMonitor,
CancellationToken cancellationToken)
@@ -583,21 +620,34 @@ namespace PowerDisplay.Common.Drivers.DDC
await Task.Delay(retryDelayMs, cancellationToken);
}
var monitors = _discoveryHelper.GetPhysicalMonitors(hMonitor);
var monitors = _discoveryHelper.GetPhysicalMonitors(hMonitor, out bool hasNullHandles);
var validationResult = ValidatePhysicalMonitors(monitors, attempt, maxRetries);
if (validationResult.IsValid)
// Success: got valid monitors with no NULL handles filtered out
if (monitors != null && !hasNullHandles)
{
return monitors;
}
if (validationResult.ShouldRetry)
// Got monitors but some had NULL handles - retry to see if API stabilizes
if (monitors != null && hasNullHandles && attempt < maxRetries - 1)
{
Logger.LogWarning($"DDC: Some monitors had NULL handles on attempt {attempt + 1}, will retry");
continue;
}
// Last attempt failed, return what we have
// No monitors returned - retry
if (monitors == null && attempt < maxRetries - 1)
{
Logger.LogWarning($"DDC: GetPhysicalMonitors returned null on attempt {attempt + 1}, will retry");
continue;
}
// Last attempt - return whatever we have (may have NULL handles filtered)
if (monitors != null && hasNullHandles)
{
Logger.LogWarning($"DDC: NULL handles still present after {maxRetries} attempts, using filtered result");
}
return monitors;
}
@@ -605,68 +655,16 @@ namespace PowerDisplay.Common.Drivers.DDC
}
/// <summary>
/// Validate physical monitors array for null handles
/// </summary>
/// <returns>Tuple indicating if valid and if should retry</returns>
private (bool IsValid, bool ShouldRetry) ValidatePhysicalMonitors(
PHYSICAL_MONITOR[]? monitors,
int attempt,
int maxRetries)
{
if (monitors == null || monitors.Length == 0)
{
if (attempt < maxRetries - 1)
{
Logger.LogWarning($"DDC: GetPhysicalMonitors returned null/empty on attempt {attempt + 1}, will retry");
}
return (false, true);
}
bool hasNullHandle = HasAnyNullHandles(monitors, out int nullIndex);
if (!hasNullHandle)
{
return (true, false); // Valid, don't retry
}
if (attempt < maxRetries - 1)
{
Logger.LogWarning($"DDC: Physical monitor [{nullIndex}] has NULL handle on attempt {attempt + 1}, will retry");
return (false, true); // Invalid, should retry
}
Logger.LogWarning($"DDC: NULL handle still present after {maxRetries} attempts, continuing anyway");
return (false, false); // Invalid but no more retries
}
/// <summary>
/// Check if any physical monitor has a NULL handle
/// </summary>
/// <param name="monitors">Array of physical monitors to check</param>
/// <param name="nullIndex">Output index of first NULL handle found, or -1 if none</param>
/// <returns>True if any NULL handle found</returns>
private bool HasAnyNullHandles(PHYSICAL_MONITOR[] monitors, out int nullIndex)
{
for (int i = 0; i < monitors.Length; i++)
{
if (monitors[i].HPhysicalMonitor == IntPtr.Zero)
{
nullIndex = i;
return true;
}
}
nullIndex = -1;
return false;
}
/// <summary>
/// Generic method to get VCP feature value
/// Generic method to get VCP feature value with optional logging.
/// </summary>
/// <param name="monitor">Monitor to query</param>
/// <param name="vcpCode">VCP code to read</param>
/// <param name="featureName">Optional feature name for logging (e.g., "color temperature", "input source")</param>
/// <param name="cancellationToken">Cancellation token</param>
private async Task<BrightnessInfo> GetVcpFeatureAsync(
Monitor monitor,
byte vcpCode,
string? featureName = null,
CancellationToken cancellationToken = default)
{
return await Task.Run(
@@ -674,19 +672,67 @@ namespace PowerDisplay.Common.Drivers.DDC
{
if (monitor.Handle == IntPtr.Zero)
{
if (featureName != null)
{
Logger.LogDebug($"[{monitor.Id}] Invalid handle for {featureName} read");
}
return BrightnessInfo.Invalid;
}
if (DdcCiNative.TryGetVCPFeature(monitor.Handle, vcpCode, out uint current, out uint max))
{
if (featureName != null)
{
var valueName = VcpValueNames.GetFormattedName(vcpCode, (int)current);
Logger.LogDebug($"[{monitor.Id}] {featureName} via 0x{vcpCode:X2}: {valueName}");
}
return new BrightnessInfo((int)current, 0, (int)max);
}
if (featureName != null)
{
Logger.LogWarning($"[{monitor.Id}] Failed to read {featureName} (0x{vcpCode:X2} not supported)");
}
return BrightnessInfo.Invalid;
},
cancellationToken);
}
/// <summary>
/// Validate that a discrete VCP value is supported by the monitor.
/// Returns null if valid, or a failure result if invalid.
/// </summary>
/// <param name="monitor">Monitor to validate against</param>
/// <param name="vcpCode">VCP code to check</param>
/// <param name="value">Value to validate</param>
/// <param name="featureName">Feature name for error messages</param>
/// <returns>Null if valid, MonitorOperationResult.Failure if invalid</returns>
private static MonitorOperationResult? ValidateDiscreteVcpValue(
Monitor monitor,
byte vcpCode,
int value,
string featureName)
{
var capabilities = monitor.VcpCapabilitiesInfo;
if (capabilities == null || !capabilities.SupportsVcpCode(vcpCode))
{
return null; // No capabilities to validate against, allow the operation
}
var supportedValues = capabilities.GetSupportedValues(vcpCode);
if (supportedValues == null || supportedValues.Count == 0 || supportedValues.Contains(value))
{
return null; // Value is valid or no discrete values defined
}
var supportedList = string.Join(", ", supportedValues.Select(v => $"0x{v:X2}"));
Logger.LogWarning($"[{monitor.Id}] {featureName} 0x{value:X2} not in supported list: [{supportedList}]");
return MonitorOperationResult.Failure($"{featureName} 0x{value:X2} not supported by monitor");
}
/// <summary>
/// Generic method to set VCP feature value
/// </summary>

23
src/modules/powerdisplay/PowerDisplay.Lib/Drivers/DDC/MonitorDiscoveryHelper.cs
View File

@@ -50,10 +50,16 @@ namespace PowerDisplay.Common.Drivers.DDC
}
/// <summary>
/// Get physical monitors for a logical monitor
/// Get physical monitors for a logical monitor.
/// Filters out any monitors with NULL handles (Windows API bug workaround).
/// </summary>
internal PHYSICAL_MONITOR[]? GetPhysicalMonitors(IntPtr hMonitor)
/// <param name="hMonitor">Handle to the logical monitor</param>
/// <param name="hasNullHandles">Output: true if any NULL handles were filtered out</param>
/// <returns>Array of valid physical monitors, or null if API call failed</returns>
internal PHYSICAL_MONITOR[]? GetPhysicalMonitors(IntPtr hMonitor, out bool hasNullHandles)
{
hasNullHandles = false;
try
{
Logger.LogDebug($"GetPhysicalMonitors: hMonitor=0x{hMonitor:X}");
@@ -89,20 +95,25 @@ namespace PowerDisplay.Common.Drivers.DDC
return null;
}
// Log each physical monitor
// Filter out NULL handles and log each physical monitor
var validMonitors = new List<PHYSICAL_MONITOR>();
for (int i = 0; i < numMonitors; i++)
{
string desc = physicalMonitors[i].GetDescription() ?? string.Empty;
IntPtr handle = physicalMonitors[i].HPhysicalMonitor;
Logger.LogDebug($"GetPhysicalMonitors: [{i}] Handle=0x{handle:X}, Desc='{desc}'");
if (handle == IntPtr.Zero)
{
Logger.LogWarning($"GetPhysicalMonitors: Monitor [{i}] has NULL handle despite successful API call!");
Logger.LogWarning($"GetPhysicalMonitors: Monitor [{i}] has NULL handle, filtering out");
hasNullHandles = true;
continue;
}
Logger.LogDebug($"GetPhysicalMonitors: [{i}] Handle=0x{handle:X}, Desc='{desc}'");
validMonitors.Add(physicalMonitors[i]);
}
return physicalMonitors;
return validMonitors.Count > 0 ? validMonitors.ToArray() : null;
}
catch (Exception ex)
{