Nack[N]: [PATCH 0/1][SRU][N][P][Q] Dell AIO backlight is not working, dell_uart_backlight module is missing

[Thibault Ferrante]

Fail to build on noble:

/build/noble/drivers/platform/x86/dell/dell-uart-backlight.c: In function 'dell_uart_startup':
/build/noble/drivers/platform/x86/dell/dell-uart-backlight.c:403:20: error: assignment to 'int (*)(struct tty_struct *, const unsigned char *, int)' from incompatible pointer type 'ssize_t (*)(struct tty_struct *, const u8 *, size_t)' {aka 'long int (*)(struct tty_struct *, const unsigned char *, long unsigned int)'} [-Werror=incompatible-pointer-types]
   403 |         uart_write = tty->driver->ops->write;
       |                    ^

Following '95713967ba52 tty: make tty_operations::write()'s count size_t', this needs to be modified:

--- a/drivers/platform/x86/dell/dell-uart-backlight.c
+++ b/drivers/platform/x86/dell/dell-uart-backlight.c
@@ -38,7 +38,7 @@ static struct tty_struct *tty;
  static struct file *ftty;
  
  unsigned int (*io_serial_in)(struct uart_port *p, int offset);
-int (*uart_write)(struct tty_struct *tty, const unsigned char *buf, int count);
+ssize_t (*uart_write)(struct tty_struct *tty, const unsigned char *buf, size_t count);
  void (*uart_flush_chars)(struct tty_struct *tty);


On 05/06/2025 05:10, AceLan Kao wrote:
> From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/ubuntu/bugs/2083800
> 
> [Impact]
> Dell AIO backlight need dell_uart_backlight module, but CONFIG_DELL_UART_BACKLIGHT is not enabled.
> 
> [Fix]
> Enable the option in the kernel config
> 
> [Test Case]
> 1. Boot Dell AIO machine to desktop
> 2. The backlight should be controllable through hotkey and/or GUI
> 
> [Where problems could occur]
> No regression.
> 
> Chia-Lin Kao (AceLan) (1):
>    UBUNTU: [Config] enable CONFIG_DELL_UART_BACKLIGHT
> 
>   debian.master/config/annotations | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>