Re: Setting a HID report via an interrupt transfer.

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[quoted lines by Greg KH on 2012/04/05 at 19:33 -0700]

>Ok, what platform are you talking about?  Specifics please.

We design for an arbitrary platform using generic higher level layers such that 
each new platform requires very little work to incorporate.

>Who is "us"?

brltty [http://mielke.cc/brltty/]

>That's a wonderful goal.  But note, that Linux already supports this
>just fine (or it should, if not, please let us know and we will fix up
>our braille interface that comes with the kernel.)

That, interestingly enough, is news to me. I'm not sure what you mean by 'Linux 
already supports braille in the kernel". It most certainly does not. Now, yes, 
On Linux we do use /dev/vcsa devices to read the screen, although, even there, 
Unicode, rather than font positions, would be a huge imrovement (we currently 
back translate font positions read from the /dev/vcsa devices to Unicode 
characters). Maybe somewhere in the kernel there's support for a specific 
braille device - I don't know. We do it all at user level so that our code can 
be portable, with only minimal dependence on the actual host platform's 
specific ways of doing things.

>Circumventing the standard apis that the Linux kernel provides for this
>type of thing is not something that you will get much help from from us
>here, as we already spent the time and energy to implement this once,
>correctly.

Before I get you too upset by saying that we don't use it, perhaps you could 
tell me exxactly what you're referring to. Maybe what you're calling braille 
support isn't at all what I'm referring to. For braille, Linux users currently 
use brltty + Orca - Orca is for the X environment and talks to brltty through 
an API.

The fact is that I chose to ask on this mailing list because I ()hopefully not 
mistakenly) assumed I would be among friends and expert consultants. If your 
only interest is to try to get us to increase the amount of our 
platform-dependent code by orders of magnitude just so that official Linux APIs 
will be used as much as possible, then you clearly don't understand either our 
needs or ourselves, and I was indeed mistaken.

>And if some platforms do not support your device, that's sad, but why
>not contact the developers of those platforms yourself?  There's nothing
>we can do about their code or interfaces here, right?

Do you really think it's the right approach for us to simply spend vast 
quantities of our personal time going after each individual platform for each 
individual device when we could just spend a couple of hours coding it once and 
knowing that it'll just work on all platforms?

Do you really think we have the resources to test each individual device on 
each individual platform each time we release a new version of our software, 
especially given that braille devices costs thousands of dollars each?

It's for reasons like these that we work to keep our drivers simple and that we 
strive for a minimum of platform-dependent code. We make sure that our drivers 
are entirely portable, and that our platform-dependent code is simple, stable, 
and trustworthy. Then, if we test a given braille device on one platform, we 
just know it'll work on all of them.

-- 
Dave Mielke           | 2213 Fox Crescent | The Bible is the very Word of God.
Phone: 1-613-726-0014 | Ottawa, Ontario   | 2011 May 21 is the End of Salvation.
EMail: dave@xxxxxxxxx | Canada  K2A 1H7   | http://Mielke.cc/now.html
http://FamilyRadio.com/                   | http://Mielke.cc/bible/
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