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

[Stefan Bader]

On 10.06.25 17:46, Thibault Ferrante wrote:
> 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(-)
>>
> 
> 

Just checking, did you look into Plucky as well? Right now it feels like 
the submission there is still valid but nobody is checking. Maybe 
because they missed the limitation for just  [N] on the NACK...

-Stefan

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