EXA pixmap alignments.
fxkuehl at gmx.de
Wed Sep 28 06:18:39 PDT 2005
Am Mittwoch, den 28.09.2005, 18:59 +1000 schrieb Benjamin Herrenschmidt:
> On Wed, 2005-09-28 at 08:32 +0200, Lars Knoll wrote:
> > Yes, that's what I currently do on nv. I also have an idea how to do
> > fb->system using PCI scatter/gather, but didn't have the time to try it out
> > up to now.
> You may want to "peek" my kernel side code for that once I'm finished...
> I hope I'll have something to play with sometimes next week-end.
> > Btw, is there any way to know if an AGP chipset supports writes
> > from card to AGP?
> Not really afaik. The radeon DRI does a sneaky test at startup, it
> "tries" to do a writeback to a scratch location and verifies if it
> actually worked. If not, it uses MMIO reads to read the scratch value
> (used for register aging afaik), if yes, it reads the one that was
> written to AGP. That's the only thing that info is used for though at
> the moment.
That test used to be unreliable on my old Radeon 7500. The test would
pass and the AGP writeback would fail later on after a few seconds of
3D. I had to work around that problem by reducing AGP speed from 4x to
| Felix Kühling <fxkuehl at gmx.de> http://fxk.de.vu |
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