linux-kernel - [PATCH] serial: 8250: probe all 16550A variants by default

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200525130238.3614179-1-olteanv@gmail.com>
Date:   Mon, 25 May 2020 16:02:38 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     gregkh@...uxfoundation.org, linux-serial@...r.kernel.org
Cc:     jslaby@...e.com, andriy.shevchenko@...ux.intel.com,
        lukas@...ner.de, heikki.krogerus@...ux.intel.com, vigneshr@...com,
        linux-kernel@...r.kernel.org, fido_max@...ox.ru,
        radu-andrei.bulie@....com
Subject: [PATCH] serial: 8250: probe all 16550A variants by default

From: Vladimir Oltean <vladimir.oltean@....com>

On NXP T1040, the UART is typically detected as 16550A_FSL64. After said
patch, it gets detected as plain 16550A and the Linux console is
completely garbled and missing characters.

So clearly, introducing the SERIAL_8250_16550A_VARIANTS config option
has broken many existing users because it has changed the default
behavior. Restore that by adding a 'default y' to this option. Users who
care about 20 ms shorter boot time can always disable it, but stop
wasting many debugging hours for people who don't care all that much.

Fixes: dc56ecb81a0a ("serial: 8250: Support disabling mdelay-filled probes of 16550A variants")
Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
 drivers/tty/serial/8250/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index af0688156dd0..89c7ecb55619 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -63,6 +63,7 @@ config SERIAL_8250_PNP
 config SERIAL_8250_16550A_VARIANTS
 	bool "Support for variants of the 16550A serial port"
 	depends on SERIAL_8250
+	default y
 	help
 	  The 8250 driver can probe for many variants of the venerable 16550A
 	  serial port. Doing so takes additional time at boot.
-- 
2.25.1