From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3F660AC4.8050003@embeddededge.com> Date: Mon, 15 Sep 2003 14:53:56 -0400 From: Dan Malek MIME-Version: 1.0 To: Jean-Denis Boyer Cc: Steffen Rumler , linuxppc Subject: Re: Problem of concurrency in arch/ppc/8260_io/uart.c References: Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Jean-Denis Boyer wrote: > I have just tested your patch on 8260 and it fixes the problem when printk is called ... The use of printk is strictly a debug function. If it is necessary to see it print out pretty, then use a different I/O path for the application or dump out the log buffer separately. Serial ports don't guarantee any transactional operation with multiple users, printk isn't any different although it does the bad thing of blocking interrupts while it processes the message. Adding this patch adds lots of interrupt latency and I would recommend against it. It appears there is a bug that should be fixed to ensure the proper synchronization of the BDs, but not with such large scale blocking of interrupts. Thanks. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/