linux-kernel - Broken serial port

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: <53A08D64.1060800@Vivier.EU>
Date:	Tue, 17 Jun 2014 20:48:04 +0200
From:	Laurent Vivier <Laurent@...ier.EU>
To:	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
CC:	Jiri Slaby <jslaby@...e.cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Seth Bollinger <sethb@...i.com>
Subject: Broken serial port

Hi,

I'm not subscribed to these mailing lists, so CC: me.

I'm playing for some days with a kernel 3.15 on an old mac performa 575
and it seems that the serial port is broken. When I log on using the
console on the serial port it seems there is an screen refresh added
after each character I send.

A little demo :

http://asciinema.org/a/10211 [at 3:20]

I bisect and I found this commit :

commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c
Author: Seth Bollinger <sethb@...i.com>
Date:   Tue Mar 25 12:55:37 2014 -0500

    serial_core: Fix conditional start_tx on ring buffer not empty

    If the serial_core ring buffer empties just as the tty layer receives
    an XOFF, then start_tx will never be called when the tty layer
    receives an XON as the serial_core ring buffer is empty.  This will
    possibly leave a few bytes trapped in the fifo for drivers that
    disable the transmitter when flow controlled.

    Signed-off-by: Seth Bollinger <sethb@...i.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>


If I revert it, all works fine :

http://asciinema.org/a/10212

Regards,
Laurent


Download attachment "signature.asc" of type "application/pgp-signature" (247 bytes)