[PATCH 3/4] EFI: console: max rows and cols user limit

[Art Nikpal]

> Why should a user set this up?

only if user need it! by default is 0 no limit

EFI console not usable for some cases: big screen sizes + mux with
serial console

for example

EFI console - fullscreen (1080P) vidconsole - SLUGGISH FRAMERATES AND NOT USABLE

CONFIG_CONSOLE_MUX=y
CONFIG_CONSOLE_NORMAL=y
CONFIG_EFI_CONSOLE_MAX_ROWS=0
CONFIG_EFI_CONSOLE_MAX_COLS=0

https://dl.khadas.com/test/uboot_efi_examples/media/07-EFI_console_example_normal_vidconsole_and_serial_multiplex_adaptation_utf_safe_SLOW_NOT_USABLE.mp4

EFI console - vidconsole with row and column limits - USABLE FRAMERATES

CONFIG_CONSOLE_MUX=y
CONFIG_CONSOLE_NORMAL=y
CONFIG_EFI_CONSOLE_MAX_ROWS=90
CONFIG_EFI_CONSOLE_MAX_COLS=25

https://dl.khadas.com/test/uboot_efi_examples/media/06-EFI_console_example_normal_vidconsole_and_serial_multiplex_adaptation_utf_safe_and_max_cols_90_limit_USABLE.mp4

Please check more information and examples about this

+ https://dl.khadas.com/test/uboot_efi_examples/#readme


On Thu, Aug 5, 2021 at 7:59 PM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 8/4/21 12:22 PM, Artem Lapkin wrote:
> > Setup the max rows and columns limit for the EFI console output.
>
> Why should a user set this up?
>
> The size of serial console depends on the remote computers console
> windows size.
>
> The size of a video console depends on the attached monitor.
>
> So we have to detect the size dynamically. Hardcoding it does not make
> any sense.
>
> Best regards
>
> Heinrich
>
> >
> > Signed-off-by: Artem Lapkin <art at khadas.com>
> > ---
> >   lib/efi_loader/Kconfig       | 12 ++++++++++++
> >   lib/efi_loader/efi_console.c |  5 +++++
> >   2 files changed, 17 insertions(+)
> >
> > diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> > index dacc3b5881..7d00d6cde5 100644
> > --- a/lib/efi_loader/Kconfig
> > +++ b/lib/efi_loader/Kconfig
> > @@ -381,4 +381,16 @@ config EFI_ESRT
> >       help
> >         Enabling this option creates the ESRT UEFI system table.
> >
> > +config EFI_CONSOLE_MAX_ROWS
> > +     int "setup console max rows"
> > +     default 0
> > +     help
> > +       Set console max rows limit or set to zero to disable limit.
> > +
> > +config EFI_CONSOLE_MAX_COLS
> > +     int "setup console max cols"
> > +     default 0
> > +     help
> > +       Set console max rows limit or set to zero to disable limit.
> > +
> >   endif
> > diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
> > index 847069212e..b5d79d788f 100644
> > --- a/lib/efi_loader/efi_console.c
> > +++ b/lib/efi_loader/efi_console.c
> > @@ -351,6 +351,11 @@ static void query_console_size(void)
> >       } else if (query_console_serial(&rows, &cols))
> >               return;
> >
> > +     if (CONFIG_EFI_CONSOLE_MAX_ROWS > 0)
> > +             rows = min(rows, CONFIG_EFI_CONSOLE_MAX_ROWS);
> > +     if (CONFIG_EFI_CONSOLE_MAX_COLS > 0)
> > +             cols = min(cols, CONFIG_EFI_CONSOLE_MAX_COLS);
> > +
> >       /* Test if we can have Mode 1 */
> >       if (cols >= 80 && rows >= 50) {
> >               efi_cout_modes[1].present = 1;
> >
>