Re: Two bugs in fbcon?

["Antonino A. Daplas" <adaplas@gmail.com>]

Ondrej Zajicek wrote:
> Hello
> 
> I found that in  kernel 2.6.16.16 is some very strange behavior in fbcon.
> I added some printks to some functions in fbcon and i found this:
> 
> I am on vt0, i have active vt0-vt3. When i modprobe fbcon (having fbdev
> driver inserted before), functions fbcon.c/fbcon_init() and
> fbcon.c/updatescrollmode() are called for each active vt.
> 
> Order is:
> fbcon_init(vt0)
> updatescrollmode(vt0)
> updatescrollmode(vt1)
> fbcon_init(vt1)
> updatescrollmode(vt2)
> fbcon_init(vt2)
> updatescrollmode(vt3)
> fbcon_init(vt3)
> 
> for vt1-vt3 updatescrollmode is called before fbcon_init which caused that
> associated struct display::vrows value is computed (in updatescrollmode()
> - fbcon.c:1970) from old vc->vc_rows (which is updated in fbcon_init()).
> 
> Now second strangeness - I am still on vt0 (immediately after modprobe fbcon),
> but during calls to bitblit.c/bit_cursor display structure associated with
> vt3 is used (in bitblit.c:244 - ops->p). Combined with previous strangeness
> (bad vrows values in vt1-vt3) i get cursor visible on bad row.
> 
> When i switch to another vt or switch resolution, then this is corrected 
> (next calls to bitblit.c/bit_cursor are using correct display structure.).
> 
> I don't understand fbcon enough to correct this problem (and be sure not to
> make some other :-)).
> 

Might be fixed in Linus's latest git tree.  Try applying this changeset:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=1a37d5f51020b9967d4b4094f6d627d0873a6469

Tony



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