27rohitb.github.io

Alienware x14 Keyboard Backlight

This is my attempt to contribute AlienFX.

• I ran lsusb to get the following:

• bash Bus 004 Device 002: ID 0bda:0328 Realtek Semiconductor Corp. USB3.0-CRW Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 009: ID 2148:7022 USB2.0 HUB Bus 003 Device 004: ID 0c45:673b Microdia Integrated_Webcam_HD Bus 003 Device 003: ID 187c:0550 Alienware Corporation LED controller Bus 003 Device 002: ID 0d62:3740 Darfon Electronics Corp. Bus 003 Device 006: ID 8087:0033 Intel Corp. Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

• This showed the PID:VID (product ID: Vendor ID) for the my alienware keyboard controller which, in my case is:

• Bus 003 Device 003: ID 187c:0550 Alienware Corporation LED controller

• After learning about descriptor, tried sudo lsusb -vd 187c:0550 and got the following:

• ```bash Bus 003 Device 003: ID 187c:0550 Alienware Corporation LED controller Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.10 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x187c Alienware Corporation idProduct 0x0550 LED controller bcdDevice 2.00 iManufacturer 1 Alienware iProduct 2 AW-ELC iSerial 3 00.01 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0029 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 0mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 3 Human Interface Device bInterfaceSubClass 0 bInterfaceProtocol 0 iInterface 0 HID Device Descriptor: bLength 9 bDescriptorType 33 bcdHID 1.11 bCountryCode 0 Not supported bNumDescriptors 1 bDescriptorType 34 Report wDescriptorLength 25 Report Descriptors: ** UNAVAILABLE ** Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0021 1x 33 bytes bInterval 10 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0021 1x 33 bytes bInterval 100 Binary Object Store Descriptor: bLength 5 bDescriptorType 15 wTotalLength 0x0021 bNumDeviceCaps 1 Platform Device Capability: bLength 28 bDescriptorType 16 bDevCapabilityType 5 bReserved 0 PlatformCapabilityUUID {d8dd60df-4589-4cc7-9cd2-659d9e648a9f} CapabilityData[0] 0x00 CapabilityData[1] 0x00 CapabilityData[2] 0x03 CapabilityData[3] 0x06 CapabilityData[4] 0x48 CapabilityData[5] 0x00 CapabilityData[6] 0x01 CapabilityData[7] 0x00 Device Status: 0x0001 Self Powered

• I came accross a windows alternative for Alienware Command Center, which mentions a controller for Alienware x17 R5 with same controller. This was to confirm and understand that this device could be interfaced using some kinda of python wrapper over USB library in linux, conincidentally which is what AlienFX project seems to do. Now I just need to understand how the device operaters, so i can modify the following:
  • cmdpacket
  • USBdriver
  • Potentially change other files if required.
• AInspired from Alienware x15 R5 post from earlier, i realised i should read more about USB descriptors and found the following resources:
  • https://www.slashdev.ca/2010/05/08/get-usb-report-descriptor-with-linux/
  • Interfacing with HID device: https://raspberrypi.stackexchange.com/questions/3465/usb-hid-device-only-firing-1-event
  • Report Descrriptor was missing, but after a bit of googling i found that we need to unbind and then report descriptor shows up.
• Ultimately i decided to dig deeper and properly learn about USB interfacing, from following sources:
  • https://www.beyondlogic.org/usbnutshell/usb5.shtml

More Linux Source:

• https://embeddedguruji.blogspot.com/