[Libdlo] Aiptek T20

[Bernie Thompson]

Hi Till,

On Wed, Oct 27, 2010 at 11:21 AM, Till Harbaum / Lists
<lists at harbaum.org> wrote:
> And yes, a kernel fb driver is the more interesting thing. I have taken a look into the udlfb driver. One major difference is that the t20 uses a 24 bit video mode. I am not sure if the kernel supports 24 bit at all, so i might have to use a 32 bit shadow buffer instead.

The kernel can support 24bpp - the mechanism is very flexible.  But
it's not clear to me what the existing user mode clients (especially
fbdev X driver) will make use of automatically or not. In particular,
I'm not sure whether 24-bit RGB or 32-bit ARGB format is better for X.
 If you find out anything, I'd be interested in hearing.

> Also it supports writing rectangles, so it should integrate nicely with an api supporting some damage reporting. And yes, of course this will be a seperate driver and not be included into the udlfb one.

Ah, good.  Yes, the DisplayLink USB 2.0 era hardware does hlines, not
rectangles in one command.

> What i don't fully understand is why there's the displaylinkfb branch. Why hasn't defio support been integrated into udlfb instead?

Defio support actually has been fully integrated into udlfb. It's all
there as a module option, and with recent fixes inside and outside
udlfb, it's actually working much better than it was 6 months ago.  So
the displaylinkfb branch is only around now for historical reference
purposes.

Regards and thanks,
Bernie