On Sun, 12 Apr 2020 at 04:49, Dave Young <dyoung@xxxxxxxxxx> wrote:
>
> When I play with terminus fonts I noticed the efi early printk does
> not work because the earlycon code assumes font width is 8.
>
> Here add the code to adapt with larger fonts. Tested with all kinds
> of kernel built-in fonts on my laptop. Also tested with a local draft
> patch for 14x28 !bold terminus font.
>
> Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
Thanks Dave. I tested this with the 10x18 font, which is utterly
broken for efifb unless I apply this patch.
I'll queue this as a fix.
> ---
> drivers/firmware/efi/earlycon.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> --- linux-x86.orig/drivers/firmware/efi/earlycon.c
> +++ linux-x86/drivers/firmware/efi/earlycon.c
> @@ -114,14 +114,16 @@ static void efi_earlycon_write_char(u32
> const u32 color_black = 0x00000000;
> const u32 color_white = 0x00ffffff;
> const u8 *src;
> - u8 s8;
> - int m;
> + int m, n, bytes;
> + u8 x;
>
> - src = font->data + c * font->height;
> - s8 = *(src + h);
> + bytes = BITS_TO_BYTES(font->width);
> + src = font->data + c * font->height * bytes + h * bytes;
>
> - for (m = 0; m < 8; m++) {
> - if ((s8 >> (7 - m)) & 1)
> + for (m = 0; m < font->width; m++) {
> + n = m % 8;
> + x = *(src + m / 8);
> + if ((x >> (7 - n)) & 1)
> *dst = color_white;
> else
> *dst = color_black;
>
