newcons fb driver

[Warner Losh]

On Mar 3, 2014, at 10:44 AM, Justin Hibbits <jhibbits at freebsd.org> wrote:

> On Mon, Mar 3, 2014 at 8:49 AM, Kurt Lidl <lidl at pix.net> wrote:
>>> In message <CAJ-Vmo=jCGUxXs_GBoCm581wTouozWE=AQ3x1wBKYM_J3_dGrg at
>>> mail.gmail.com>
>>> 
>>> , Adrian Chadd writes:
>>> 
>>>> .. i'm pretty sure there was a reason for why it's done in byte sizes.
>>>> Maybe speak to phk?
>>> 
>>> 
>>> Buggy video hardware, which does not do larger writes correctly,
>>> the most recent one being an Intel Laptop, but I can't remember which.
>>> 
>>> At the very least, byte writes needs to be a boot-time option.
>> 
>> 
>> Intel Atom boards, as I recall:
>> 
>> http://freshbsd.org/commit/freebsd/r237203
>> 
>> -Kurt
> 
> All great knowledge, but really only answers half of what I'm looking
> for (always good to know potential pitfalls).  Assuming a
> tunable/sysctl is added, what's the best way to optimize from my
> original post?  Use a backing buffer (potentially with a tunable to
> not)?  Or assume we don't support background images, and write the
> background color in the masked pixels?

Most of the issues are with the CHARACTER buffer, not the actual frame (pixel) buffer…

Warner