public static Tuple <ushort, ushort> I2CGetDDCCIBrightness(GPUOutput output)
{
// DDC/CI protocol
var data = new byte[]
{
DDCCIDataLengthMask | 0x02, // 2 byte follows
DDCCIReadValue,
DDCCIBrightnessIndex,
0x00 // Checksum, to be calculated later
};
var register = new[] { DDCCIRegisterAddress };
I2CInfoV3.FillDDCCIChecksum(DDCCISlaveAddress, register, data);
output.WriteI2C(
null,
true,
DDCCISlaveAddress,
register,
data
);
Thread.Sleep(100);
data = output.ReadI2C(
null,
true,
DDCCISlaveAddress,
new byte[] { 0 },
11
);
// Check if this is the response to the request that we sent
if (data[0] != DDCCISlaveAddress << 1)
{
return(null);
}
var length = data[1] & (DDCCIDataLengthMask - 1);
data = data.Skip(2).Take(length).ToArray();
// Irrelevant response
if (data[2] != DDCCIBrightnessIndex)
{
return(null);
}
// Check if this operation is unsupported
if (data[1] != 0)
{
return(null);
}
var max = (data[4] << 8) | data[5];
var current = (data[6] << 8) | data[7];
return(new Tuple <ushort, ushort>((ushort)current, (ushort)max));
}
public static bool I2CSetDDCCIBrightness(GPUOutput output, ushort brightness)
{
var range = I2CGetDDCCIBrightness(output);
if (range == null)
{
return(false);
}
// Normalize value in range
brightness = (ushort)Math.Max(Math.Min((int)brightness, range.Item2), 0);
// Already has same brightness value
if (range.Item1 == brightness)
{
return(true);
}
Thread.Sleep(100);
// DDC/CI protocol
var data = new byte[]
{
DDCCIDataLengthMask | 0x04, // 4 byte follows
DDCCIChangeValue,
DDCCIBrightnessIndex,
(byte)(brightness >> 8), // Brightness value (High Byte)
(byte)(brightness & 0xFF), // Brightness value (Low Byte)
0x00 // Checksum, to be calculated later
};
var register = new[] { DDCCIRegisterAddress };
I2CInfoV3.FillDDCCIChecksum(DDCCISlaveAddress, register, data);
output.WriteI2C(
null,
true,
DDCCISlaveAddress,
register,
data
);
return(true);
}