Re: [PATCH next] ACPICA: AML Parser: Remove spurious precision from format used to dump parse trees

[Petr Mladek]

On Thu 2026-03-26 20:18:30, david.laight.linux@xxxxxxxxx wrote:
> From: David Laight <david.laight.linux@xxxxxxxxx>
> 
> The debug code in acpi_ps_delete_parse_tree() uses ("%*.s", level * 4, " ")
> to indent traces.
> POSIX requires the empty precision be treated as zero, but the kernel treats
> is as 'no precision specified'.
> Change to ("%*s", level * 4, "") since there is additional whitespace and no
> reason to indent by one space when level is zero.
> 
> --- a/drivers/acpi/acpica/pswalk.c
> +++ b/drivers/acpi/acpica/pswalk.c
> @@ -49,8 +49,7 @@ void acpi_ps_delete_parse_tree(union acpi_parse_object *subtree_root)
>  
>  				/* This debug option will print the entire parse tree */
>  
> -				acpi_os_printf("      %*.s%s %p", (level * 4),
> -					       " ",
> +				acpi_os_printf("      %*s%s %p", (level * 4), "",
>  					       acpi_ps_get_opcode_name(op->
>  								       common.
>  								       aml_opcode),

The change has no visible effect. The precision defines how many
characters are copied from the given string. It does not matter
here because the given string is empty "". The number of added
spaces ' ' is defined by the field width parameter (level * 4).

Anyway, the change makes sense:

Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>

Best Regards,
Petr