Re: [PATCH] efi earlyprintk fix
From: Matt Fleming
Date: Mon Nov 04 2013 - 05:38:06 EST
On Sun, 03 Nov, at 08:16:47PM, Dave Young wrote:
>
> there's below one line shift problem:
>
> ACPI=0xdabfe000 ACPI 2.0=0xdabfe014 SMBIOS=0xdaa9e000
> [ 0.000000] efi:
>
> In fact check efi_y and the lfb_height should be compared at the begin of the
> loop of early_efi_write
Hmm... this is interesting. I can't produce this on any of my machines.
Where did you see this? What hardware?
> Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
> ---
> arch/x86/platform/efi/early_printk.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-2.6.orig/arch/x86/platform/efi/early_printk.c
> +++ linux-2.6/arch/x86/platform/efi/early_printk.c
> @@ -106,6 +106,15 @@ early_efi_write(struct console *con, con
> if (count > linemax)
> count = linemax;
>
> + if (efi_y + font->height >= si->lfb_height) {
> + u32 i;
> +
> + efi_y -= font->height;
> + early_efi_scroll_up();
> +
> + for (i = 0; i < font->height; i++)
> + early_efi_clear_scanline(efi_y + i);
> + }
> for (h = 0; h < font->height; h++) {
> unsigned int n, x;
>
> @@ -142,15 +151,6 @@ early_efi_write(struct console *con, con
> efi_y += font->height;
> }
>
> - if (efi_y + font->height >= si->lfb_height) {
> - u32 i;
> -
> - efi_y -= font->height;
> - early_efi_scroll_up();
> -
> - for (i = 0; i < font->height; i++)
> - early_efi_clear_scanline(efi_y + i);
> - }
> }
> }
Notice how we figure out the initial value of efi_y...
static __init int early_efi_setup(struct console *con, char *options)
{
struct screen_info *si;
u16 xres, yres;
u32 i;
si = &boot_params.screen_info;
xres = si->lfb_width;
yres = si->lfb_height;
....
efi_y = rounddown(yres, font->height) - font->height;
Every time we enter early_efi_write(), we should have enough space to
write one line, so I'm not at all sure what's going wrong with your
display.
--
Matt Fleming, Intel Open Source Technology Center
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