newcons fb driver

[Justin Hibbits]

On Wed, Mar 5, 2014 at 7:02 AM, Bruce Evans <brde at optusnet.com.au> wrote:
> On Thu, 6 Mar 2014, Bruce Evans wrote:
>
>> On Tue, 4 Mar 2014, Justin Hibbits wrote:
>>>
>>> Without some kind of optimization, newcons on powerpc is unacceptably
>>> slow.
>>
>>
>> How slow is that exactly?  If the frame buffer speed is 50MB/S, then
>> 16x8 characters with 256 colors can be written at 390K/S.  This is
>> acceptable.  If the frame buffer is much slower than that, then it is
>> too slow, at least without hardware scrolling.
>
>
> I forgot to mention that u$ doesn't solve this problem in WinXP.  The
> speed is not too bad in normal mode (only about 30 times slower than
> syscons - the scrolling speed is 30000 lines/second instead of 1000000).
> But in safe mode, a simple graphics driver is used and it is horribly
> slow.  Safe mode with command prompt gives an MSDOS prompt in a
> maximized terminal window, so the problem is very noticeable (the
> scrolling speed is 4 lines per second = 12 seconds per screenful).
> Apparently normal mode uses acceleration to be not very slow, but safe
> mode is too simple to do that.  The FreeBSD console driver needs to
> be even simpler so that it works as a low level console.
>
> Bruce

The ofwfb syscons driver is much faster than newcons, so a frame
buffer can be made relatively fast (within reason).  It's newcons
that's slow, and my assumption currently is the byte-oriented writes
instead of word size.

- Justin