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From: Robert S. <r.s...@pe...> - 2008-12-23 12:39:02
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Guennadi,
On Tue, Dec 23, 2008 at 06:47:32PM +0800, Eric Miao wrote:
> PXA27x and later processors support overlay1 and overlay2 on-top of the
> base framebuffer (although under-neath the base is also possible).
[...]
> + Applications should follow the sequence below to operate an overlay
> + framebuffer:
> +
> + a. open("/dev/fb[1-2]", ...)
> + b. ioctl(fd, FBIOGET_VSCREENINFO, ...)
> + c. modify 'var' with desired parameters:
> + 1) var->xres and var->yres
> + 2) larger var->yres_virtual if more memory is required,
> + usually for double-buffering
> + 3) var->nonstd for starting (x, y) and color format
> + 4) var->{red, green, blue, transp} if RGB mode is to be used
> + d. ioctl(fd, FBIOPUT_VSCREENINFO, ...)
> + e. ioctl(fd, FBIOGET_FSCREENINFO, ...)
> + f. mmap
> + g. ...
That looks like a good pattern to me and we should re-use it on i.MX.
rsc
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