[PATCH v3 1/3] efi_loader: Avoid overwriting previous outputs on console screen clearing
Simon Glass
sjg at chromium.org
Fri Nov 4 20:08:07 CET 2022
Hi,
On Fri, 4 Nov 2022 at 02:07, Jan Kiszka <jan.kiszka at siemens.com> wrote:
>
> From: Jan Kiszka <jan.kiszka at siemens.com>
>
> Before clearing the screen, ensure that no previous output of firmware
> or UEFI programs will be overwritten on serial devices or other
> streaming consoles. This helps generating complete boot logs.
>
> Tested regarding multi-output against qemu-x86_defconfig.
>
> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> ---
> lib/efi_loader/efi_console.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
Please see this thread...some things need to be improved in this area.
https://patchwork.ozlabs.org/project/uboot/patch/20221022092058.106052-1-heinrich.schuchardt@canonical.com/
>
> diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
> index 4d08dd3763a..6ce0fcc168d 100644
> --- a/lib/efi_loader/efi_console.c
> +++ b/lib/efi_loader/efi_console.c
> @@ -461,10 +461,16 @@ static efi_status_t EFIAPI efi_cout_set_attribute(
> }
>
> /**
> - * efi_cout_clear_screen() - clear screen
> + * efi_clear_screen() - clear screen
> */
> static void efi_clear_screen(void)
> {
> + unsigned int row;
> +
> + /* Avoid overwriting previous outputs on streaming consoles */
> + for (row = 1; row < efi_cout_modes[efi_con_mode.mode].rows; row++)
> + printf("\n");
> +
> /*
> * The Linux console wants both a clear and a home command. The video
> * uclass does not support <ESC>[H without coordinates, yet.
> --
> 2.35.3
>
Regards,
SImon
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