Re: Framebuffer console performance

[Gary Thomas <gary@mlbassoc.com>]

On Sat, 2005-04-16 at 05:26 -0600, Gary Thomas wrote:
> On Fri, 2005-04-15 at 12:57 +0800, Antonino A. Daplas wrote: 
> > On Friday 25 March 2005 06:14, Gary Thomas wrote:
> > > I have a non-standard framebuffer (i.e. I wrote the driver,
> > > based on the au1000 driver) running on 2.4.27.  When I run
> > > virtual consoles on it, I see sluggish scroll performance.
> > > I get quite acceptable performance when the system first
> > > comes up, e.g. during the system initialization messages,
> > > but not long afterwards the scrolling slows down.  It can
> > > get continually worse, eventually ending up at a crawl.
> > 
> > When the system starts up, the scroll mode is 'redraw'.  This mode is
> > acceptable, not too slow and not too fast either, whatever the hardware is.
> > 
> > After starting up, the scroll mode changes depending on the driver.  Most
> > probably, it is using ypan which is not too great on systems without
> > accelerated rectangle moves and framebuffer reads are slow.
> > 
> > Try setting vyres == yres using fbset and see if that helps.

Thanks for getting back to me on this.

This does seem to have been the problem.  I made a few tweaks to
my driver's setup and now it does not switch into slow mode (I actually
think it was going into __SCROLL_YMOVE mode instead of __SCROLL_YREDRAW)

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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