accessibilities first tests - many questions

Guylhem Aznar olpc at
Sat Aug 18 11:19:11 EDT 2007


On 8/18/07, Jordan Crouse <jordan.crouse at> wrote:
> 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!)

I'd prefer not touching the kernel yet and concentrating on the
software side. If you have a chance to add this to sysfs, I will test
it. Basically, I would like to compare the screen readability in as
many different modes as possible, letting people freely switch between
display modes in different situations so they can chose the one they
best like.

It's just an experiment - I would like to have data proving users
actually prefer using the display when the algorithm is enabled.
Sometimes you have surprising results.

> 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.

Hmm - that I won't touch at all. If you plan to add support sometime
in the future, I think it could be quite handy to let applications
lower the refresh rate at will (ex: when switching pages in ebook
mode, a lower refresh rate would save power, while during a page read,
the dcon display mode could be used)

> > I have done some shell scripts to test my stuff (ugly but handy, esp

Here it is BTW.

> 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.

I thought about it but I wasn't 100% certain. Ok, at least that is sure :-)

Regarding the zoom/overlay, I will see what can be done in software.

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