[PATCH 1/1] efi_loader: avoid EFI_CALL() for clearing screen

[Jan Kiszka]

On 15.10.22 12:15, Heinrich Schuchardt wrote:
> Carve out function efi_clear_screen.
> 

This does not motivate *why* you prefer to not use efi_cout_clear_screen
anymore.

A side effect of this is that the screen will not longer be filled with
a new background color, leading to lines that are written with that new
background but only for the actual text length. Attached a screenshot to
visualize this. Was that intended? Not saying it's necessarily critical.

Jan

PS: This is with proper console scrolling in place to avoid overwriting.
Will send an update of my related patch soon.

> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  lib/efi_loader/efi_console.c | 26 +++++++++++++++++---------
>  1 file changed, 17 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
> index 3354b217a9..6d4784e140 100644
> --- a/lib/efi_loader/efi_console.c
> +++ b/lib/efi_loader/efi_console.c
> @@ -460,6 +460,20 @@ static efi_status_t EFIAPI efi_cout_set_attribute(
>  	return EFI_EXIT(EFI_SUCCESS);
>  }
>  
> +/**
> + * efi_cout_clear_screen() - clear screen
> + */
> +static void efi_clear_screen(void)
> +{
> +	/*
> +	 * The Linux console wants both a clear and a home command. The video
> +	 * uclass does not support <ESC>[H without coordinates, yet.
> +	 */
> +	printf(ESC "[2J" ESC "[1;1H");
> +	efi_con_mode.cursor_column = 0;
> +	efi_con_mode.cursor_row = 0;
> +}
> +
>  /**
>   * efi_cout_clear_screen() - clear screen
>   *
> @@ -475,13 +489,7 @@ static efi_status_t EFIAPI efi_cout_clear_screen(
>  {
>  	EFI_ENTRY("%p", this);
>  
> -	/*
> -	 * The Linux console wants both a clear and a home command. The video
> -	 * uclass does not support <ESC>[H without coordinates, yet.
> -	 */
> -	printf(ESC "[2J" ESC "[1;1H");
> -	efi_con_mode.cursor_column = 0;
> -	efi_con_mode.cursor_row = 0;
> +	efi_clear_screen();
>  
>  	return EFI_EXIT(EFI_SUCCESS);
>  }
> @@ -510,7 +518,7 @@ static efi_status_t EFIAPI efi_cout_set_mode(
>  		return EFI_EXIT(EFI_UNSUPPORTED);
>  
>  	efi_con_mode.mode = mode_number;
> -	EFI_CALL(efi_cout_clear_screen(this));
> +	efi_clear_screen();
>  
>  	return EFI_EXIT(EFI_SUCCESS);
>  }
> @@ -536,7 +544,7 @@ static efi_status_t EFIAPI efi_cout_reset(
>  	efi_con_mode.attribute = 0x07;
>  	printf(ESC "[0;37;40m");
>  	/* Clear screen */
> -	EFI_CALL(efi_cout_clear_screen(this));
> +	efi_clear_screen();
>  
>  	return EFI_EXIT(EFI_SUCCESS);
>  }

-- 
Siemens AG, Technology
Competence Center Embedded Linux
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