From 8f592ada59b321d248391bae175cd78a12972223 Mon Sep 17 00:00:00 2001
From: Dave Young <dyoung@redhat.com>
Date: Sun, 12 Apr 2020 10:49:27 +0800
Subject: [PATCH] efi/earlycon: Fix early printk for wider fonts
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@redhat.com>
Link: https://lore.kernel.org/r/20200412024927.GA6884@dhcp-128-65.nay.redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/earlycon.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c
index 5d4f84781aa0..a52236e11e5f 100644
--- a/drivers/firmware/efi/earlycon.c
+++ b/drivers/firmware/efi/earlycon.c
@@ -114,14 +114,16 @@ static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h)
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;