Re: [Linux-fbdev-devel] [PATCH] Tile Blitting

[Geert U. <ge...@li...>]

On Thu, 27 Feb 2003, James Simmons wrote:
> > On Don, 2003-02-27 at 15:15, Antonino Daplas wrote: 
> > > On Thu, 2003-02-27 at 09:18, James Simmons wrote:
> > >  
> > > > > Thus, the restriction that the buffer must be completely copied by the
> > > > > driver before returning.  And because of this restriction, an extra copy
> > > > > which might be unnecessary cannot be avoided (this was noted by Petr).
> > > > > 
> > > > > Treating the buffer as a ringbuffer, we eliminate these restrictions.
> > > > 
> > > > I didn't realize that the below was a ringbuffer implementation. The name
> > > > threw me off. 
> > > 
> > > Well, it's not strictly a ringbuffer implementation.  This would require
> > > a head and tail pointer where fbcon will adjust the tail and the
> > > driver/hardware will adjust the head.  This will be very difficult to
> > > implement in a device independent manner.  So we just cheat by issuing
> > > an fb_sync() per loop to flush all pending commands.
> > 
> > That still seems suboptimal though. What the DRM often does is have the
> > chip write an age value to a scratch register when it's done processing
> > something. Maybe something like that could be used to avoid waiting for
> > the chip to go idle at all?
> 
> Don't waste your time. I'm removing all the changes that have been done 
> since 2.5.51. After that I will no longer be co-maintainter of the 
> framebuffer layer. 

Are you sure about that?!?!?

What about adding a pointer to a

    struct con_ops {
      set_font();
      putc();
      putcs();
    } 
    
to struct fb_info as an interim solution, until tile blitting has matured? That
would make Petr (matroxfb) and Davem (sbusfb) happy?

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li...

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds