From: Christian Borntraeger <borntraeger@de.ibm.com>
Organization: IBM
To: Scott Wood <scottwood@freescale.com>
Subject: Re: [PATCH] hvc_console: returning 0 from put_chars is not an error
Date: Thu, 15 Oct 2009 21:26:27 +0200
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Cc: Timur Tabi <timur@freescale.com>, linuxppc-dev@ozlabs.org,
       brueckner@linux.vnet.ibm.com, Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Am Donnerstag 15 Oktober 2009 20:57:45 schrieb Scott Wood:
> Doing it in the backend requires the backend to know whether it's being
> called for printk or for user I/O.  In the latter case, we don't want to
> spin, but rather wait for an IRQ (or poll with a timer if there's no IRQ).

Right. Now you have me convinced that we really should have some logic in 
hvc_console because, its the only place that knows if it came from printk or 
user.

About the backends, there are some that spin until the text is delivered (e.g. 
virtio) , others can drop (e.g. iucv is a connection oriented protocol and it 
will (and has to) drop if there is no connection). 
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