Put the info forth in an Amiga ppc related thread, agpmode=-1 is also needed on the Pegasos 2, need do some research/googling but is it safe to say its broken for all non x86 platforms?
Including those replies here: ---- Hi Christian and Mike, for my personal experiences on Pegasos2 and MacMini G4 the performance was good on 3D and 2D but need the agpmode=-1 or the system freeze adding the agpmode=-1 make loose performances but make the system working this because the gpu without that append was over working it was look like software overclocked. About agp macs a guy on ubuntuforums boost his performance adding this to the kernel append "quiet splash radeon.modeset=0 video=radeonfb:1280x960-32@60 " About Pegasos2 i had it with 9800pro and the machine was running great. Alex i know is a geek with this machine that i dont have any moore or better i have another one died :- --- Hi Luigi. Thanks. Remember the modeset=0 flag my self from a while back, had to be appended to either the kernel or as an option the the module. What a sorry state.. I think agpmode=-1 masks a bunch of issues, degrading performance due to some hittage of the cpu unnecessary, thats my suspicion anyway. likely if ever a fix is found it will reveal a bunch of other issues is my fear. ---- On 5 February 2016 at 07:49, Denis Kirjanov <k...@linux-powerpc.org> wrote: > On 2/5/16, Mike <michael.hel...@gmail.com> wrote: > > Hi. > > Managed to get the Radeon R300 running on mesa 11.1.1 with an old 2013 > > patch from Michel Dànzer, next problem is of course enabling agpmode, > > running with pci-mode with radeon.agpmode=-1 works, but is of course > slow, > > and seems to load the cpu a lot. > > For me nouveau on quad pmac is also broken for years(?) :/ > > > > > Upon initial investigation i could not initially believe agp could be > this > > this broken for this long, until i found this. > > "committed with Ben Skeggs on Feb 26, 2013" > > > https://github.com/DespairFactor/bullhead/commit/650e1203c11354ba84d69ba445abc0efcfe3890a > > > http://lxr.free-electrons.com/source/drivers/gpu/drm/nouveau/nouveau_agp.c?v=4.2 > > #ifdef __powerpc__ > > /* Disable AGP by default on all PowerPC machines for > > * now -- At least some UniNorth-2 AGP bridges are > > * known to be broken: DMA from the host to the card > > * works just fine, but writeback from the card to the > > * host goes straight to memory untranslated bypassing > > * the GATT somehow, making them quite painful to deal > > * with... > > */ > > if (nouveau_agpmode == -1) > > return false; > > #endif > > > > and now later this: > > > https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/nouveau/nvkm/subdev/pci/agp.c > > #ifdef __powerpc__ > > /* Disable AGP by default on all PowerPC machines for now -- At > > * least some UniNorth-2 AGP bridges are known to be broken: > > * DMA from the host to the card works just fine, but writeback > > * from the card to the host goes straight to memory > > * untranslated bypassing that GATT somehow, making them quite > > * painful to deal with... > > */ > > mode = 0; > > #endif > > > > All seems to point to serious issues had around the time of change to ums > > to kms and a serious regression hitting the linux kernel? No? > > > > Cheers > > -Mike > > >
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