wadimw · May 18, 2025 14:38 · kPepis · Mar 2, 2022 · jaknas · Mar 29, 2022
diff --git a/adaptMonitorBrightness-M27Q.py b/adaptMonitorBrightness-M27Q.py
 #!/usr/local/bin/python3

 # For Gigabyte M27Q KVM connected over USB-C
 #
 # Reads brightness value of builtin display from system, adapts it (Lunar-style) and sends over USB command to external display
 #
 # You need PyUSB and PyObjC
 #
 # Not much testing was done so far, only on MBP A1990 15" 2019 i7 555X
 #
 # Works only on MacOS, but set_brightness_M27Q() can be used on any platform that supports PyUSB.
 from sys import platform
 from time import sleep

 import m27q
 import builtinbrt

 # https://github.com/alin23/Lunar/blob/master/Lunar/Data/Util.swift
 def map_number(number, from_low, from_high, to_low, to_high):
    if number >= from_high:
        return to_high
    elif number <= from_low:
        return to_low
    elif to_low < to_high:
        diff = to_high - to_low
        from_diff = from_high - from_low
        return (number - from_low) * diff / from_diff + to_low
    else:
        diff = to_high - to_low
        from_diff = from_high - from_low
        return (number - from_low) * diff / from_diff + to_low

 # Algorithm copied over from Lunar
 # https://www.desmos.com/calculator/zciiqhtnov
 # https://github.com/alin23/Lunar/blob/master/Lunar/Data/Display.swift
 def adapt_brightness(old_brightness):
 	# Adjust parameters here
 	int_clip_min = 35	# 0-100
 	int_clip_max = 95	# 0-100
 	ext_brt_min = 0		# 0-100
 	ext_brt_max = 100	# 0-100
 	offset = -50		# -100-100

 	# Float division
 	old_brightness = float(old_brightness)

 	# Clipping
 	old_brightness = map_number(old_brightness, int_clip_min, int_clip_max, 0, 100)

 	# Curve factor
 	factor = 1-(float(offset)/100)

 	new_brightness = ((((old_brightness/100)*(ext_brt_max-ext_brt_min)+ext_brt_min)/100)**factor)*100
 	new_brightness = int(round(new_brightness))

 	return max(min(100, new_brightness), 0)

 def main():
 	if platform != "darwin":
 		raise Exception("This script works only on MacOS.")
 	else:
 		try:
 			builtin = builtinbrt.BuiltinBrightness()
 			stored_brightness = None
 			while True:
 				# Get builtin display brightness
 				builtin_brightness = builtin.get_brightness()
 				# Calculate value for external display
 				new_brightness = adapt_brightness(builtin_brightness)

 				print("Builtin:", builtin_brightness, "M27Q:", new_brightness, "was:", stored_brightness)

 				with m27q.MonitorControl() as external:
 					if new_brightness != stored_brightness:
 						external.transition_brightness(new_brightness)
 					stored_brightness = new_brightness
 					sleep(3)
 		except IOError as e:
 			import sys
 			t, v, tb = sys.exc_info()
 			print(v)
 			# Wait a minute so that launchd won't try to revive process non-stop
 			sleep(60)
 			raise e.with_traceback(tb)


 if __name__ == "__main__":
    main()
diff --git a/builtinbrt.py b/builtinbrt.py
 # Builtin Brightness for MacOS
 import objc
 import CoreFoundation
 from Foundation import NSBundle

 IOKIT_FRAMEWORK = "com.apple.framework.IOKit"
 DISPLAY_CONNECT = b"IODisplayConnect"

 class BuiltinBrightness:
 	# Import IOKit functions only once
 	_iokit_imported = False

 	# Load functions used in fetching brightness
 	@staticmethod
 	def import_iokit():
 		if not BuiltinBrightness._iokit_imported:
 			iokit = NSBundle.bundleWithIdentifier_(IOKIT_FRAMEWORK)
 			functions = [
 			    ("IOServiceGetMatchingService", b"II@"),
 				("IOServiceMatching", b"@*"),
 			    ("IODisplayGetFloatParameter", b"iII@o^f"),
 			    ("IOObjectRelease", b"iI")
 			]
 			variables = [
 				("kIOMasterPortDefault", b"I"),
 			    # ("kIODisplayBrightnessKey", b"*") # "brightness", had some trouble loading it so using string literal instead
 			]

 			objc.loadBundleFunctions(iokit, globals(), functions)
 			objc.loadBundleVariables(iokit, globals(), variables)
 			globals()['kIODisplayBrightnessKey'] = "brightness"
 		BuiltinBrightness._iokit_imported = True

 	# Make sure necessary functions were imported
 	def __init__(self):
 		BuiltinBrightness.import_iokit()

 	# Read brightness level of builtin (first) display
 	def get_brightness(self) -> int:
 		# Get first available display IOService
 		service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching(DISPLAY_CONNECT))
 		if not service:
 			raise IOError("No IODisplayConnect services found")
 		
 		(error, brightness) = IODisplayGetFloatParameter(service, 0, kIODisplayBrightnessKey, None)
 		if error:
 			raise IOError(f"Couldn't get parameter {kIODisplayBrightnessKey} from service {service}, error {error}")

 		error = IOObjectRelease(service)
 		if error:
 			raise IOError(f"Failed to release IOService {service}")

 		return int(brightness*100)
diff --git a/m27q.py b/m27q.py
 # For Gigabyte M27Q KVM connected over USB-C
 #
 # Recreates messages captured with Wireshark from OSD Sidekick on Windows.
 # Requires PyUSB.
 # Further testing should be done.
 # Code based mostly on https://www.linuxvoice.com/drive-it-yourself-usb-car-6/
 # and https://github.com/pyusb/pyusb/blob/master/docs/tutorial.rst
 #
 # Can be used on any platform that supports PyUSB.
 #
 # OSD getter, setter and KVM toggle based on @P403n1x87 findings (https://github.com/P403n1x87/m27q)

 import usb.core
 import usb.util
 import typing as t
 from time import sleep

 class MonitorControl:
 	def __init__(self):
 		self._VID=0x2109 # (VIA Labs, Inc.)
 		self._PID=0x8883 # USB Billboard Device
 		self._dev=None
 		self._usb_delay = 50/1000 # 50 ms sleep after every usb op
 		self._min_brightness = 0
 		self._max_brightness = 100
 		self._min_volume = 0
 		self._max_volume = 100
 		

 	# Find USB device, set config
 	def __enter__(self):
 		# Find device
 		self._dev=usb.core.find(idVendor=self._VID, idProduct=self._PID)
 		if self._dev is None:
 			raise IOError(f"Device VID_{self._VID}&PID_{self._PID} not found")
 		
 		# Deach kernel driver
 		self._had_driver = False
 		try:
 			if self._dev.is_kernel_driver_active(0):
 				self._dev.detach_kernel_driver(0)
 				self._had_driver = True
 		except Exception as e:
 			pass
 		
 		# Set config (1 as discovered with Wireshark)
 		self._dev.set_configuration(1)
 		return self

 	# Optionally reattach kernel driver
 	def __exit__(self, exc_type, exc_val, exc_tb):
 		# Reattach kernel driver
 		if self._had_driver:
 			self._dev.attach_kernel_driver(0)
 		# Release device
 		usb.util.dispose_resources(self._dev)

 	def usb_write(self, b_request: int, w_value: int, w_index: int, message: bytes):
 		bm_request_type = 0x40
 		if not self._dev.ctrl_transfer(bm_request_type, b_request, w_value, w_index, message) == len(message):
 			raise IOError("Transferred message length mismatch")
 		sleep(self._usb_delay)

 	def usb_read(self, b_request: int, w_value: int, w_index: int, msg_length: int):
 		bm_request_type = 0xC0
 		data = self._dev.ctrl_transfer(bm_request_type, b_request, w_value, w_index, msg_length)
 		sleep(self._usb_delay)
 		return data

 	def get_osd(self, data: t.List[int]):
 		self.usb_write(
 			b_request=178,
 			w_value=0,
 			w_index=0,
 			message=bytearray([0x6E, 0x51, 0x81 + len(data), 0x01]) + bytearray(data),
 		)
 		data = self.usb_read(b_request=162, w_value=0, w_index=111, msg_length=12)
 		return data[10]

 	def set_osd(self, data: bytearray):
 		self.usb_write(
 			b_request=178,
 			w_value=0,
 			w_index=0,
 			message=bytearray([0x6E, 0x51, 0x81 + len(data), 0x03] + data),
 		)

 	def set_brightness(self, brightness: int):
 		self.set_osd(
 			[
 				0x10,
 				0x00,
 				max(self._min_brightness, min(self._max_brightness, brightness)),
 			]
 		)

 	def get_brightness(self):
 		return self.get_osd([0x10])

 	def transition_brightness(self, to_brightness: int, step: int = 3):
 		current_brightness = self.get_brightness()
 		diff = abs(to_brightness - current_brightness)
 		if current_brightness <= to_brightness:
 			step = 1 * step # increase
 		else:
 			step = -1 * step # decrease
 		while diff >= abs(step):
 			current_brightness += step
 			self.set_brightness(current_brightness)
 			diff -= abs(step)
 		# Set one last time
 		if current_brightness != to_brightness:
 			self.set_brightness(to_brightness)

 	def get_kvm_status(self):
 		return self.get_osd([224, 105])

 	def set_kvm_status(self, status):
 		self.set_osd([224, 105, status])

 	def toggle_kvm(self):
 		self.set_kvm_status(1 - self.get_kvm_status())
	#!/usr/local/bin/python3

	# For Gigabyte M27Q KVM connected over USB-C
	#
	# Reads brightness value of builtin display from system, adapts it (Lunar-style) and sends over USB command to external display
	#
	# You need PyUSB and PyObjC
	#
	# Not much testing was done so far, only on MBP A1990 15" 2019 i7 555X
	#
	# Works only on MacOS, but set_brightness_M27Q() can be used on any platform that supports PyUSB.
	from sys import platform
	from time import sleep

	import m27q
	import builtinbrt

	# https://github.com/alin23/Lunar/blob/master/Lunar/Data/Util.swift
	def map_number(number, from_low, from_high, to_low, to_high):
	if number >= from_high:
	return to_high
	elif number <= from_low:
	return to_low
	elif to_low < to_high:
	diff = to_high - to_low
	from_diff = from_high - from_low
	return (number - from_low) * diff / from_diff + to_low
	else:
	diff = to_high - to_low
	from_diff = from_high - from_low
	return (number - from_low) * diff / from_diff + to_low

	# Algorithm copied over from Lunar
	# https://www.desmos.com/calculator/zciiqhtnov
	# https://github.com/alin23/Lunar/blob/master/Lunar/Data/Display.swift
	def adapt_brightness(old_brightness):
	# Adjust parameters here
	int_clip_min = 35 # 0-100
	int_clip_max = 95 # 0-100
	ext_brt_min = 0 # 0-100
	ext_brt_max = 100 # 0-100
	offset = -50 # -100-100

	# Float division
	old_brightness = float(old_brightness)

	# Clipping
	old_brightness = map_number(old_brightness, int_clip_min, int_clip_max, 0, 100)

	# Curve factor
	factor = 1-(float(offset)/100)

	new_brightness = ((((old_brightness/100)(ext_brt_max-ext_brt_min)+ext_brt_min)/100)factor)100
	new_brightness = int(round(new_brightness))

	return max(min(100, new_brightness), 0)

	def main():
	if platform != "darwin":
	raise Exception("This script works only on MacOS.")
	else:
	try:
	builtin = builtinbrt.BuiltinBrightness()
	stored_brightness = None
	while True:
	# Get builtin display brightness
	builtin_brightness = builtin.get_brightness()
	# Calculate value for external display
	new_brightness = adapt_brightness(builtin_brightness)

	print("Builtin:", builtin_brightness, "M27Q:", new_brightness, "was:", stored_brightness)

	with m27q.MonitorControl() as external:
	if new_brightness != stored_brightness:
	external.transition_brightness(new_brightness)
	stored_brightness = new_brightness
	sleep(3)
	except IOError as e:
	import sys
	t, v, tb = sys.exc_info()
	print(v)
	# Wait a minute so that launchd won't try to revive process non-stop
	sleep(60)
	raise e.with_traceback(tb)


	if __name__ == "__main__":
	main()
	# Builtin Brightness for MacOS
	import objc
	import CoreFoundation
	from Foundation import NSBundle

	IOKIT_FRAMEWORK = "com.apple.framework.IOKit"
	DISPLAY_CONNECT = b"IODisplayConnect"

	class BuiltinBrightness:
	# Import IOKit functions only once
	_iokit_imported = False

	# Load functions used in fetching brightness
	@staticmethod
	def import_iokit():
	if not BuiltinBrightness._iokit_imported:
	iokit = NSBundle.bundleWithIdentifier_(IOKIT_FRAMEWORK)
	functions = [
	("IOServiceGetMatchingService", b"II@"),
	("IOServiceMatching", b"@*"),
	("IODisplayGetFloatParameter", b"iII@o^f"),
	("IOObjectRelease", b"iI")
	]
	variables = [
	("kIOMasterPortDefault", b"I"),
	# ("kIODisplayBrightnessKey", b"*") # "brightness", had some trouble loading it so using string literal instead
	]

	objc.loadBundleFunctions(iokit, globals(), functions)
	objc.loadBundleVariables(iokit, globals(), variables)
	globals()['kIODisplayBrightnessKey'] = "brightness"
	BuiltinBrightness._iokit_imported = True

	# Make sure necessary functions were imported
	def __init__(self):
	BuiltinBrightness.import_iokit()

	# Read brightness level of builtin (first) display
	def get_brightness(self) -> int:
	# Get first available display IOService
	service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching(DISPLAY_CONNECT))
	if not service:
	raise IOError("No IODisplayConnect services found")

	(error, brightness) = IODisplayGetFloatParameter(service, 0, kIODisplayBrightnessKey, None)
	if error:
	raise IOError(f"Couldn't get parameter {kIODisplayBrightnessKey} from service {service}, error {error}")

	error = IOObjectRelease(service)
	if error:
	raise IOError(f"Failed to release IOService {service}")

	return int(brightness*100)
	# For Gigabyte M27Q KVM connected over USB-C
	#
	# Recreates messages captured with Wireshark from OSD Sidekick on Windows.
	# Requires PyUSB.
	# Further testing should be done.
	# Code based mostly on https://www.linuxvoice.com/drive-it-yourself-usb-car-6/
	# and https://github.com/pyusb/pyusb/blob/master/docs/tutorial.rst
	#
	# Can be used on any platform that supports PyUSB.
	#
	# OSD getter, setter and KVM toggle based on @P403n1x87 findings (https://github.com/P403n1x87/m27q)

	import usb.core
	import usb.util
	import typing as t
	from time import sleep

	class MonitorControl:
	def __init__(self):
	self._VID=0x2109 # (VIA Labs, Inc.)
	self._PID=0x8883 # USB Billboard Device
	self._dev=None
	self._usb_delay = 50/1000 # 50 ms sleep after every usb op
	self._min_brightness = 0
	self._max_brightness = 100
	self._min_volume = 0
	self._max_volume = 100


	# Find USB device, set config
	def __enter__(self):
	# Find device
	self._dev=usb.core.find(idVendor=self._VID, idProduct=self._PID)
	if self._dev is None:
	raise IOError(f"Device VID_{self._VID}&PID_{self._PID} not found")

	# Deach kernel driver
	self._had_driver = False
	try:
	if self._dev.is_kernel_driver_active(0):
	self._dev.detach_kernel_driver(0)
	self._had_driver = True
	except Exception as e:
	pass

	# Set config (1 as discovered with Wireshark)
	self._dev.set_configuration(1)
	return self

	# Optionally reattach kernel driver
	def __exit__(self, exc_type, exc_val, exc_tb):
	# Reattach kernel driver
	if self._had_driver:
	self._dev.attach_kernel_driver(0)
	# Release device
	usb.util.dispose_resources(self._dev)

	def usb_write(self, b_request: int, w_value: int, w_index: int, message: bytes):
	bm_request_type = 0x40
	if not self._dev.ctrl_transfer(bm_request_type, b_request, w_value, w_index, message) == len(message):
	raise IOError("Transferred message length mismatch")
	sleep(self._usb_delay)

	def usb_read(self, b_request: int, w_value: int, w_index: int, msg_length: int):
	bm_request_type = 0xC0
	data = self._dev.ctrl_transfer(bm_request_type, b_request, w_value, w_index, msg_length)
	sleep(self._usb_delay)
	return data

	def get_osd(self, data: t.List[int]):
	self.usb_write(
	b_request=178,
	w_value=0,
	w_index=0,
	message=bytearray([0x6E, 0x51, 0x81 + len(data), 0x01]) + bytearray(data),
	)
	data = self.usb_read(b_request=162, w_value=0, w_index=111, msg_length=12)
	return data[10]

	def set_osd(self, data: bytearray):
	self.usb_write(
	b_request=178,
	w_value=0,
	w_index=0,
	message=bytearray([0x6E, 0x51, 0x81 + len(data), 0x03] + data),
	)

	def set_brightness(self, brightness: int):
	self.set_osd(
	[
	0x10,
	0x00,
	max(self._min_brightness, min(self._max_brightness, brightness)),
	]
	)

	def get_brightness(self):
	return self.get_osd([0x10])

	def transition_brightness(self, to_brightness: int, step: int = 3):
	current_brightness = self.get_brightness()
	diff = abs(to_brightness - current_brightness)
	if current_brightness <= to_brightness:
	step = 1 * step # increase
	else:
	step = -1 * step # decrease
	while diff >= abs(step):
	current_brightness += step
	self.set_brightness(current_brightness)
	diff -= abs(step)
	# Set one last time
	if current_brightness != to_brightness:
	self.set_brightness(to_brightness)

	def get_kvm_status(self):
	return self.get_osd([224, 105])

	def set_kvm_status(self, status):
	self.set_osd([224, 105, status])

	def toggle_kvm(self):
	self.set_kvm_status(1 - self.get_kvm_status())