accel again.

[James Simmons <jsimmons@edgeglobal.com>]

Well I did my homework on spinlocks and see what you mean by using
spinlocks to handle accel and framebuffer access. So just before I have
fbcon access the accel engine I could do this right?

In fb.h 
--------
struct fb_info {
	...
	struct vm_area_struct vm_area
	...
}
--------

In fbcon.c

/* I going to access accel engine */
spin_lock(&fb_info->vm_area->vm_mm->page_table_lock); 

/* accessing accel engine */
....
/* done with accel engine */
spin_unlock(&fb_info->vm_area->vm_mm->page_table_lock);

Now this would lock the framebuffer correct? So if a process would try to
acces the framebuffer it would be put to sleep while its doing accels. Is
this basically what I need to do or is their something more that I am
missing. 

Their also exist the possiblity that the accel engine in the kernel and
the accel registers from userland could be access at the same time. This
means that spin_lock could be called twice. Any danger in this? Then some
accel engines use a interuppt to flush their FIFO. So a 
spin_lock_irqsave(&fb_info->vm_area->vm_mm->page_table_lock, flags);
should always be used correct?

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