linux-kernel - Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx

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

Message-ID: <20140929095440.GB13142@linutronix.de>
Date:	Mon, 29 Sep 2014 11:54:40 +0200
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	Frans Klaver <frans.klaver@...ns.com>
Cc:	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Peter Hurley <peter@...leysoftware.com>, tony@...mide.com,
	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	balbi@...com, linux-serial@...r.kernel.org,
	linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Alan Cox <alan@...ux.intel.com>
Subject: Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround
 for AM33xx

* Frans Klaver | 2014-09-29 10:50:42 [+0200]:

>This version fixes the console things for us. It also increases the
>amount of data we can push over the serial port. If I push the data
>towards our requirements, we're not there yet. I get the "too much work
>for irq" notice still. However, I don't think you'd need to be fixing
>that in this series (or at all). We had similar issues there with
>omap-serial as well.
>
>As far as I'm concerned, this is
>
>Tested-by: Frans Klaver <frans.klaver@...ns.com>

Thanks a lot.
There is a patch named "ARM: edma: unconditionally ack the error
interrupt". I have the feeling that this is not really required once we
delay set_termios. I couldn't reproduce the bug with beagleblack with my
usual test case.

For your "too much work for irq" problem: Could you add trace_printk()
in tx/rx dma start/complete, and irq routine? The interresting part is
what is the irq routine doing once entered. It might be a condition that
is ignored at first and "acked" later while serving another event. Or it
is really doing something and this is more or less "legal".

>Thanks,
>Frans

Sebastian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/