Name | Size | Last modified (GMT) | Description | |
Parent directory | 2024-10-29 14:06:25 | |||
Makefile | 486 bytes | 2024-10-29 14:06:25 | ||
README | 1770 bytes | 2024-10-29 14:06:25 | ||
dell-uart-backlight-emulator.c | 3956 bytes | 2024-10-29 14:06:25 |
1 Emulator for DELL0501 UART attached backlight controller 2 -------------------------------------------------------- 3 4 Dell All In One (AIO) models released after 2017 use a backlight controller 5 board connected to an UART. 6 7 In DSDT this uart port will be defined as: 8 9 Name (_HID, "DELL0501") 10 Name (_CID, EisaId ("PNP0501") 11 12 With the DELL0501 indicating that we are dealing with an UART with 13 the backlight controller board attached. 14 15 This small emulator allows testing 16 the drivers/platform/x86/dell/dell-uart-backlight.c driver without access 17 to an actual Dell All In One. 18 19 This requires: 20 1. A (desktop) PC with a 16550 UART on the motherboard and a standard DB9 21 connector connected to this UART. 22 2. A DB9 NULL modem cable. 23 3. A second DB9 serial port, this can e.g. be a USB to serial converter 24 with a DB9 connector plugged into the same desktop PC. 25 4. A DSDT overlay for the desktop PC replacing the _HID of the 16550 UART 26 ACPI Device() with "DELL0501" and adding a _CID of "PNP0501", see 27 DSDT.patch for an example of the necessary DSDT changes. 28 29 With everything setup and the NULL modem cable connected between 30 the 2 serial ports run: 31 32 ./dell-uart-backlight-emulator <path-to-/dev/tty*S#-for-second-port> 33 34 For example when using an USB to serial converter for the second port: 35 36 ./dell-uart-backlight-emulator /dev/ttyUSB0 37 38 And then (re)load the dell-uart-backlight driver: 39 40 sudo rmmod dell-uart-backlight; sudo modprobe dell-uart-backlight dyndbg 41 42 After this check "dmesg" to see if the driver correctly received 43 the firmware version string from the emulator. If this works there 44 should be a /sys/class/backlight/dell_uart_backlight/ directory now 45 and writes to the brightness or bl_power files should be reflected 46 by matching output from the emulator.
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