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From: mhornung.linux@gmail.com (mhornung.linux at gmail.com)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Delay in Printk Messages.
Date: Sat, 28 Jun 2014 23:58:16 +0200	[thread overview]
Message-ID: <20140628215814.GA28057@googlemail.com> (raw)
In-Reply-To: <53AEFC79.2020308@gmail.com>

Hello Arun Kumar,

On Sat, 28. Jun 23:03, Arun Kumar wrote:
> I am able to read my printk messages in the kernel buffer only after 
> unloading the module..
> Is there some reason or configuration behind this.
> 
> I used a simple kernel module with only init and exit functions, and 
> after loading the module i cannot see the message printed by the 
> "module_init" function in the output given by "dmesg -c" I can see them 
> only after i unload the module.
> 

Since you do not provide your code I have to guess that your print
statement looks like this:

	  pr_debug("Hello World!");

Please notice that printk doesn't flush until a trailing newline is
provided (Linux Device Drivers Chapter 4). So maybe this is what you want:

	  pr_debug("Hello World!\n");

> i wait for around 15-20 seconds for the init message but it only shows 
> up on removing the module.
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

With best regards

Michael Hornung

      parent reply	other threads:[~2014-06-28 21:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-28 17:33 Delay in Printk Messages Arun Kumar
2014-06-28 17:39 ` Kristofer Hallin
2014-06-28 17:43   ` Aruna Hewapathirane
2014-06-28 21:58 ` mhornung.linux at gmail.com [this message]

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