From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Simmons <jsimmons@infradead.org>
Date: Tue, 16 Mar 2010 13:56:38 +0000
Subject: Re: [Linux-fbdev-devel] drm_fb_helper: Impossible to change video
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To: =?ISO-8859-15?Q?Michel_D=E4nzer?= <michel@daenzer.net>
Cc: Linux Fbdev development list <linux-fbdev@vger.kernel.org>, Paulius Zaleckas <paulius.zaleckas@gmail.com>, Michal Suchanek <hramrach@centrum.cz>, Alex Deucher <alexdeucher@gmail.com>, DRI development list <dri-devel@lists.sourceforge.net>


> > The fb_ops can only be called from fbcon or the fbdev userland interface. 
> > The fbcon calls should only happen when the VC is in KD_TEXT mode. Now 
> > with the DRM backend we have the advantage of creating a mapping seperate 
> > from the console mapping. A fb_open/fb_close could be used to cleaning up 
> > the userland mmap as well as handle the console pinning. We can supply 
> > your own fb_mmap hook.
> 
> Again, the issue is not userspace but that fb_ops hooks can be called
> from interrupt context etc.

This should not happen. The VT layer is protected from calling in the 
interrupt context. TNor does fbcon call any fb_ops methods from a irq.
I have to look at the fbdev drivers but to my knowledge none touch any 
memory while in a context. Have you seen this happen before? Please let me 
know do I can fix it right a way.