Double buffering amba-clcd fb driver

Double buffering amba-clcd fb driver

[Ramya Segar]

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Hi,
I m a realtive newcomer to linux and device drivers in particular.
I have doubts regrading how to enable double buffering in the fb driver for
amba-clcd.
I m interested in knowing how to enable double bufefring, where two buffers
are allocated and swapped during vertical blanking period (this is how i
understood it).
As I understand it, the dbe extension of XFree86 X server provides software
double buffering, where each window has two buffers, a front and back..
If you can point me to any documentation on this, it would be a great help..

Thanks in adavnce,
Ramya.

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Re: Double buffering amba-clcd fb driver

[Geert Uytterhoeven]

On Wed, 18 Oct 2006, Ramya Segar wrote:
> I m a realtive newcomer to linux and device drivers in particular.
> I have doubts regrading how to enable double buffering in the fb driver for
> amba-clcd.
> I m interested in knowing how to enable double bufefring, where two buffers
> are allocated and swapped during vertical blanking period (this is how i
> understood it).
> As I understand it, the dbe extension of XFree86 X server provides software
> double buffering, where each window has two buffers, a front and back..
> If you can point me to any documentation on this, it would be a great help..

If your graphics engine supports virtual screens and panning, one simple way is
this:
  - Make the virtual vertical resolution (fb_var_screeninfo.yres_virtual) 2
    times the real vertical resolution (fb_var_screeninfo.yres)
  - Use panning to switch from the top (fb_var_screeninfo.yoffset = 0) to the
    bottom (fb_var_screeninfo.yoffset = fb_var_screeninfo.yres) and vice versa

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

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Re: Double buffering amba-clcd fb driver

[Ramya Segar]

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Thank you Geert for your quick response.
I ll try this out..
--
Ramya.

On 10/18/06, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> On Wed, 18 Oct 2006, Ramya Segar wrote:
> > I m a realtive newcomer to linux and device drivers in particular.
> > I have doubts regrading how to enable double buffering in the fb driver
> for
> > amba-clcd.
> > I m interested in knowing how to enable double bufefring, where two
> buffers
> > are allocated and swapped during vertical blanking period (this is how i
> > understood it).
> > As I understand it, the dbe extension of XFree86 X server provides
> software
> > double buffering, where each window has two buffers, a front and back..
> > If you can point me to any documentation on this, it would be a great
> help..
>
> If your graphics engine supports virtual screens and panning, one simple
> way is
> this:
>   - Make the virtual vertical resolution (fb_var_screeninfo.yres_virtual)
> 2
>     times the real vertical resolution (fb_var_screeninfo.yres)
>   - Use panning to switch from the top (fb_var_screeninfo.yoffset = 0) to
> the
>     bottom (fb_var_screeninfo.yoffset = fb_var_screeninfo.yres) and vice
> versa
>
> Gr{oetje,eeting}s,
>
>                                                 Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@linux-m68k.org
>
> 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
>
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> _______________________________________________
> Linux-fbdev-devel mailing list
> Linux-fbdev-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel
>

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