I'm Using the vesafb module, as the target hardware ( to which i do not currently have access ) has no hardware acceleration.

I know the vesafb driver is capable of smooth graphics, as directfb is able to run on it, with no hardware accelleration and provide perfectly smooth animation, No image tearing or flickering.

I have studdied the DirectFB source, and SDL's fbcon source.

They use the FBIOPUT_VSCREENINFO ioctl to first set the vyres to double that of the visible yres, then pan the display for a double buffer effect.

This ioctl works fine, returning 0, however after testing the screen info with FBIOGET_VSCREENINFO, the yres and vyres values are unchanged.

Thanks for replying.

On 12/27/06, Torgeir Veimo <torgeir@pobox.com> wrote:

On 27 Dec 2006, at 02:14, Chris Stones wrote:

I am strugling to find documentation, but from reading linux/fb.h it seems the only way to do this is with the FBIOGET_VBLANK ioctl.... however, for unknown reasons, this is always returning -1 ( ERROR ! ) 

That means that the framebuffer module used doesn't support that ioctl. It's not implemented for all framebuffer modules. The matrox framebuffer has it, and I have posted a patch in the past for the radeon framebuffer. 

Which framebuffer module are you using?

Torgeir Veimo

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