Displayport i2c Bus access returns errors when using smbus functions

I’m trying to send I2C commands through my monitor’s displayport with the i2c_smbus_write_byte commands , but I’m getting I / O errors.
I2C_FUNC_SMBUS_WRITE_BYTE function test give no errors.

I have no issue when i use the hdmi port or when i use the i2c ioctl (ddcutil) …