Re: [Linux-fbdev-devel] Some questions

[Antonino D. <ad...@po...>]

On Sat, 2003-03-08 at 01:00, Thomas Winischhofer wrote:
> >>Why you used info->var.yres_virtual (and not the adapted 
> >>var.yres_virtual) in fbcon_resize() is beyond me, BTW.
> > 
> > Because info->var will _always_ contain the correct var, so we trust
> > that above all.
> 
> Then I must have misunderstood the code. You submit var (and not 
> info->var) to fb_set_var, so it is that var that will be treated by 
> check_var and used for set_par. Since check_var() may (and does) change 
> the yres_virtual according to the desired resolution/depth and so on, I 
> thought it might be more correct to use it instead of info->var...
> 

Note that fbcon_resize made a copy of info->var, then modified it
according to the requested width and height.  Then it goes through a
test if it needs an fb_set_var or not.  So info->var and the modified
var can be different if fb_set_var() wasn't called at all.  If it indeed
went through fb_set_var(), the var returned from check_var() will be
placed automatically to info->var before calling set_par().  So, yes, in
this case, info->var and the adjusted var will be the same.

Of course, in this particular code it is not important whichever var is
used because we're only interested in yres_virtual.  But using info->var
instead of the adjusted var is safer because it is guaranteed to be
always correct.

BTW: I'll check the patch against vesafb and let you know.

Tony