# Re: Re: \[macro@ds2.pg.gda.pl: Re: PMAG-A support?\]

- From: Maciej W. Rozycki \<hidden\>
- Date: 2003-09-01 12:03:24 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2003/09/13451666
- Thread: https://ratatoskr.run/linux-fbdev/2003/08/13451536/t.md

```text
On Sat, 30 Aug 2003, Thiemo Seufer wrote:

> > > >  I've looked at the patch and have changed the barriers as I deem
> > > > appropriate.  But while doing this, I've noticed the code is insonsistent
> > > > in a few places -- has it been successfully verified on real hardware?
> 
> There are some mb() calls in your patch, I believe a rmb()/wmb() is
> enough in those cases.

 They are there because you don't really know if the previous access (if
any) to the addressed chip was a read or a write.  So you need to use a
barrier that works for both.  Please let me know if I got any specific
ones wrong, though.

> > > It works on my /260. Which parts look weird to you?
> > 
> > 1. bt431_write_reg_inc() uses u16 for value, even though it only uses 8
> > bits (which of course makes all the calls in bt431_init_cursor() dubious). 
> >
> > 2. bt431_load_cursor_sprite() loads control registers instead of the
> > cursor map. 
> 
> The hardware cursor is still unused. The code there is very experimental,
> and your version is surely an imporvement. :-)

 Hmm, but doesn't it lead to a garble where cursor is expected to be? 

  Maciej

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +



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