accessibilities first tests - many questions

Jordan Crouse jordan.crouse at
Fri Aug 17 19:34:41 EDT 2007

On 17/08/07 11:56 +0200, Guylhem Aznar wrote:
> Hello,
> The only things I don't know yet how to do with the DCON :
>  - how to disable the smoothing algorithm applied in color mode

We didn't enable this ability in the sysfs/ interface.  I have never
been too clear on what the actual practical uses are for something like
this, so the control never got added. 

In a pinch, you can use the i2c-tools utilities to write to the device
directly (use at your own risk!) 

>  - how to reduce the framerate (for ex for ebook reading, but it could
> also be handy in text mode)

This is difficult to do - since it would involve synchronizing with the 
video driver which with X and the framebuffer driver will invariably result
in a screen glitch (note that just switching the rate on the DCON itself
doesn't cause a glitch - its the software that is braindead
here).  But we don't have any support for this in the kernel.

> I have done some shell scripts to test my stuff (ugly but handy, esp
> Regarding power management, I have a problem with the DCON freeze
> before suspend to ram: the display looks like frozen, but when I query
> the freeze file just before and right after the suspend, I only get 0
> while I should get 1.

Thats because the DCON driver does the freeze on its own while the system
is suspending, and it restores it long before userspace gets unfrozen, 
so from your perspective, it will always be 0.

> Can I also ask for some help there?
> Regarding the X being used, I am curious to know if there is a way to
> do live screen scaling ("zoom" function, where the whole screen is
> magnified) ? Ideally, it would be hardware managed, but that could
> also be done by software.

No.  The hardware doesn't have any way of zooming the graphics screen,
so you would have to do it in software, which is probably not ideal on
the Geode. 

Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.

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