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Fix DDR5 SPD misidentification as DDR4 #12

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Fix DDR5 SPD misidentification as DDR4 #12

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7 changes: 7 additions & 0 deletions RAMSPDToolkit/SPD/DDR4Accessor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,13 @@ public DDR4Accessor(SMBusInterface bus, byte address)
/// <returns>True if DDR4 is available at specified address; false otherwise.</returns>
public static bool IsAvailable(SMBusInterface bus, byte address)
{
//On DDR5 hubs offset 0x02 is the device revision, not the memory type.
//Its value can overlap the DDR4 memory type codes.
if (DDR5Accessor.HasHubDeviceType(bus, address))
{
return false;
}

int value;

//Select first page
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25 changes: 23 additions & 2 deletions RAMSPDToolkit/SPD/DDR5Accessor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,12 @@ public DDR5Accessor(SMBusInterface bus, byte address)
/// <returns>True if DDR5 is available at specified address; false otherwise.</returns>
public static bool IsAvailable(SMBusInterface bus, byte address)
{
//Check device type before changing the page
if (!HasHubDeviceType(bus, address))
{
return false;
}

//Read current page
int status = RetryReadByteData(bus, address, DDR5Constants.SPD_DDR5_MREG_VIRTUAL_PAGE, SPDConstants.SPD_DATA_RETRIES, out byte page);

Expand Down Expand Up @@ -129,13 +135,28 @@ public static bool IsAvailable(SMBusInterface bus, byte address)
}
}

return true;
}

#endregion

#region Internal

/// <summary>
/// Detects if a DDR5 SPD Hub is available at specified address without changing the page.
/// </summary>
/// <param name="bus">SMBus to check for RAM.</param>
/// <param name="address">Address to check.</param>
/// <returns>True if a DDR5 SPD Hub is available at specified address; false otherwise.</returns>
internal static bool HasHubDeviceType(SMBusInterface bus, byte address)
{
//Try read most significant byte
//Result should be 0x51
var result = RetryReadByteData(bus, address, DDR5Constants.SPD_DDR5_DEVICE_TYPE_MOST, SPDConstants.SPD_DATA_RETRIES, out byte ddr5Magic);

if (result < 0)
{
LogSimple.LogTrace($"{nameof(DDR5Accessor)}.{nameof(IsAvailable)} failed to read {nameof(DDR5Constants.SPD_DDR5_DEVICE_TYPE_MOST)} due to error {result}.");
LogSimple.LogTrace($"{nameof(DDR5Accessor)}.{nameof(HasHubDeviceType)} failed to read {nameof(DDR5Constants.SPD_DDR5_DEVICE_TYPE_MOST)} due to error {result}.");
}

//Try read least significant byte
Expand All @@ -144,7 +165,7 @@ public static bool IsAvailable(SMBusInterface bus, byte address)

if (result < 0)
{
LogSimple.LogTrace($"{nameof(DDR5Accessor)}.{nameof(IsAvailable)} failed to read {nameof(DDR5Constants.SPD_DDR5_DEVICE_TYPE_LEAST)} due to error {result}.");
LogSimple.LogTrace($"{nameof(DDR5Accessor)}.{nameof(HasHubDeviceType)} failed to read {nameof(DDR5Constants.SPD_DDR5_DEVICE_TYPE_LEAST)} due to error {result}.");
}

//Is it a DDR5 module ?
Expand Down