[PATCH v2] efi_loader: Allow disabling ANSI console queries via Kconfig

[Ilias Apalodimas]

On Wed, 18 Mar 2026 at 16:25, Michal Simek <michal.simek at amd.com> wrote:
>
> Commit 4cb724364030 ("efi_loader: Disable ANSI output for tests")
> introduced efi_console_set_ansi() to suppress ANSI escape sequences
> during unit tests. Extend this mechanism to be configurable via a new
> Kconfig option CONFIG_EFI_CONSOLE_DISABLE_ANSI.
>
> When CONFIG_EFI_CONSOLE_DISABLE_ANSI is enabled,
> efi_console_set_ansi(false) is called at the start of
> efi_setup_console_size(). This prevents query_console_serial() from
> sending ANSI escape sequences to the terminal, using default 25x80
> dimensions instead. This is useful for platforms where the serial
> console cannot handle ANSI queries.
>
> Signed-off-by: Michal Simek <michal.simek at amd.com>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>

> ---
>
> Changes in v2:
> - Replace runtime 'no_ansi' env variable with compile-time
>   CONFIG_EFI_CONSOLE_DISABLE_ANSI Kconfig option (Ilias, Peter)
>
>  lib/efi_loader/Kconfig       | 11 +++++++++++
>  lib/efi_loader/efi_console.c |  3 +++
>  2 files changed, 14 insertions(+)
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index b5f81e0ff530..bae98e07d238 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -576,6 +576,17 @@ config EFI_EBBR_2_1_CONFORMANCE
>         help
>           Enabling this option adds the EBBRv2.1 conformance entry to the ECPT UEFI table.
>
> +config EFI_CONSOLE_DISABLE_ANSI
> +       bool "Disable ANSI escape sequence queries for console size"
> +       help
> +         Select this option to disable ANSI escape sequence queries for
> +         detecting serial console size. When enabled,
> +         efi_setup_console_size() will not send ANSI escape sequences to
> +         the terminal and will use default 25x80 dimensions instead.
> +         This is useful for platforms where the serial console cannot
> +         properly handle ANSI queries, causing boot delays or garbled
> +         output.
> +
>  config EFI_SCROLL_ON_CLEAR_SCREEN
>         bool "Avoid overwriting previous output on clear screen"
>         help
> diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
> index 068d1a0a7b74..a798d5604a31 100644
> --- a/lib/efi_loader/efi_console.c
> +++ b/lib/efi_loader/efi_console.c
> @@ -365,6 +365,9 @@ void efi_setup_console_size(void)
>         int rows = 25, cols = 80;
>         int ret = -ENODEV;
>
> +       if (IS_ENABLED(CONFIG_EFI_CONSOLE_DISABLE_ANSI))
> +               efi_console_set_ansi(false);
> +
>         if (IS_ENABLED(CONFIG_VIDEO))
>                 ret = query_vidconsole(&rows, &cols);
>         if (ret) {
> --
> 2.43.0
>
> base-commit: 0d7293676b1e644b9b9ee2e45fb1ed10337cef31
> branch: debian-sent3