git: 34d55be0747b - main - boot0: add a note about BIOS-supported serial rates

From: Ed Maste <emaste_at_FreeBSD.org>
Date: Tue, 15 Aug 2023 22:46:04 UTC
The branch main has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=34d55be0747ba4452f9611ca88fe21e9d94be266

commit 34d55be0747ba4452f9611ca88fe21e9d94be266
Author:     Ed Maste <emaste@FreeBSD.org>
AuthorDate: 2023-08-15 22:42:22 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2023-08-15 22:45:58 +0000

    boot0: add a note about BIOS-supported serial rates
    
    We plan to increase the default serial rate to 115200 (see review
    D36295) but early boot components that use BIOS interfaces do not
    support higher rates.  Add a note to that effect.
    
    Reported by:    imp
    Sponsored by:   The FreeBSD Foundation
---
 stand/i386/boot0/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stand/i386/boot0/Makefile b/stand/i386/boot0/Makefile
index 5e82d7b6ae67..83eee46dfd11 100644
--- a/stand/i386/boot0/Makefile
+++ b/stand/i386/boot0/Makefile
@@ -56,7 +56,7 @@ ORG=	0x600
 # 2      stop bits (set = 2, clear = 1)
 # 1-0    data bits (00 = 5, 01 = 6, 10 = 7, 11 = 8)
 .if !defined(BOOT_BOOT0_COMCONSOLE_SPEED)
-BOOT_COMCONSOLE_SPEED?=	9600
+BOOT_COMCONSOLE_SPEED?=	9600	# BIOS interfaces do not support higher rates.
 .if ${BOOT_COMCONSOLE_SPEED} == 9600
 BOOT_BOOT0_COMCONSOLE_SPEED=	"7 << 5 + 3"
 .elif ${BOOT_COMCONSOLE_SPEED} == 4800