On Sun, 2005-06-05 at 09:58 -0400, Vladimir Dergachev wrote: > >> Which way can memory controller be misprogrammed ? The part that concerns > >> us are positions of Video RAM, AGP and System Ram in Radeon address space. > >> (these are specified by RADEON_MC_AGP_LOCATION, RADEON_MC_FB_LOCATION). > >> > >> The memory controller *always* assumes that system RAM (accessible via > >> PCI) starts at 0. So, if RADEON_MC_FB_LOCATION, for example, is set to 0 > >> then we have video RAM overlapping system RAM. > > > > Yup, and that is not recommended. We program it differently on r200 but > > for some reason, X still does that hack to put it down at 0 on r300. > > I wonder why. I always assumed that r300 should behave similarly to r200 - > at least I can't see where the switch is. I certainly have not put any > switches to change the behaviour (unless it was a mistake).
I think people originally had problems with the r200 code on r300, which might be related to the use of tiled mode by the firmware on some r300 based setups (at least on macs). It seems that just mucking around MC_FB_* etc... without actually disabling or reconfiguring tiling properly locks up the card. I think we need to be smarter here. We probably need to change MC_FB_LOCATION etc... in the actual mode set sequence (and thus save/restore them on console switch). We should probably make sure nothing is accessing memory while doing the change (that is set the proper bits to disable access to MC by the CRTC, which should be easy in the mode setting which is already wrapped in blanks). > >> Note that old driver was able to test whether mirroring works, so it > >> would correspond to behaviour of RV350 cards. It could be that R300 cards > >> are more touchy in this regard. > > > > Might be worth trying to fallback to non-mirrored setup and see if that > > helps. > > The most puzzling thing is that lockup is not immediate (as I would have > expected) and that it works on some chips.. > > best > > Vladimir Dergachev > > > > > Ben. > > > > > > > > > > ------------------------------------------------------- > > This SF.Net email is sponsored by: NEC IT Guy Games. How far can you > > shotput > > a projector? How fast can you ride your desk chair down the office luge > > track? > > If you want to score the big prize, get to know the little guy. > > Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20 > > -- > > _______________________________________________ > > Dri-devel mailing list > > Dri-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/dri-devel > > ------------------------------------------------------- This SF.Net email is sponsored by: NEC IT Guy Games. How far can you shotput a projector? How fast can you ride your desk chair down the office luge track? If you want to score the big prize, get to know the little guy. Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20 -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
