Re: [PATCH] efi earlyprintk fix

From: Matt Fleming
Date: Fri Nov 08 2013 - 05:37:00 EST


On Thu, 07 Nov, at 08:09:06PM, Dave Young wrote:
> Here is my debug message about the efifb params (all hex values):
> [ 0.000000] efi fb lfb width: 280
> [ 0.000000] efi fb lfb height: 1e0
> [ 0.000000] efi fb lfb base: e0000000
> [ 0.000000] efi fb lfb linelength: a00
> [ 0.000000] efi fb font height: 10
> [ 0.000000] efi fb font width: 8
>
> The problem looks related to the pr_cont(), here is what I observed:
> [ 0.000000] efi: EFI v2.00 by Lenovo
> ACPI=0xdabfe000 ACPI 2.0=0xdabfe014 SMBIOS=0xdaa9e000
> [ 0.000000] efi:
>
> After relooking the code, below fix is more reasonable than my original one,
> But I still confused why it only happens on this machine.

Dave, could you try this patch?

---

diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c
index 6599a0027b76..81b506d5befd 100644
--- a/arch/x86/platform/efi/early_printk.c
+++ b/arch/x86/platform/efi/early_printk.c
@@ -142,7 +142,7 @@ early_efi_write(struct console *con, const char *str, unsigned int num)
efi_y += font->height;
}

- if (efi_y + font->height >= si->lfb_height) {
+ if (efi_y + font->height > si->lfb_height) {
u32 i;

efi_y -= font->height;
--
Matt Fleming, Intel Open Source Technology Center
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