[Nouveau] [Bug 54437] [NVC8] linux-nouveau2.6 (3.6.0-rc4) : GTX580 : Xorg freezes when using accel

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=54437

--- Comment #16 from Kelly Doran <kel.p.doran at gmail.com> ---
(In reply to comment #13)
> (In reply to comment #12)
> > This bug is affecting me also, see the last duplicated bug. Any progress in
> > fixing this? Maybe some help in testing (for ex.) required?
> 
> It's a bit of a mystery unfortunately. Adding to the annoyance, Ben said
> that it does work just fine on his NVC8, although he has the less powerful
> versions. Could be something with high ROP/TPC/GPC counts not being handled.
> (Or multiple PARTs?)
> 
> That might actually be an interesting experiment -- before loading nouveau,
> mask out a bunch of the units and see if it helps. If it does, find the
> "breaking" point.
> 
> This is the code that computes that stuff:
> 
> http://cgit.freedesktop.org/~darktama/nouveau/tree/nvkm/engine/graph/nvc0.
> c#n1330
> 
> 	priv->rop_nr = (nv_rd32(priv, 0x409604) & 0x001f0000) >> 16;
> 	priv->gpc_nr =  nv_rd32(priv, 0x409604) & 0x0000001f;
> 	for (i = 0; i < priv->gpc_nr; i++) {
> 		priv->tpc_nr[i]  = nv_rd32(priv, GPC_UNIT(i, 0x2608));
> 		priv->tpc_total += priv->tpc_nr[i];
> 	}
> 
> Step 1: Print out the various values (i.e. number of ROPs, GPCs, and the
> per-GPC TPC counts).
> Step 2: Artificially lower them (to, e.g., 1) and see if it helps. If it
> does, figure out which of the values matter and where the breaking points
> are.
> 
> If it doesn't help, perhaps the units need to be disabled a little harder,
> e.g. by setting 0x22584/0x22588.

Heres the printed out values:
[    3.185455] Rop nr: 6
[    3.185457] Gpc nr: 4
[    3.185460] Tpc nr for gpc 0: 4
[    3.185463] Tpc nr for gpc 1: 4
[    3.185466] Tpc nr for gpc 2: 4
[    3.185469] Tpc nr for gpc 3: 4

I tried setting them all to 1, the card freezes pretty much immediately after
logging into kwin (which is when I suspect opengl rendering starts), although
oddly enough there was no read fault in the dmesg.  I also tried setting them
all to 2, and it froze pretty quickly too, and the machine became completely
unrecoverable.  Note that I also tried using the blob firmware with all values
set to 2, so I think not having them at their natural amounts simply pisses the
card off.  Didn't try directly disabling stuff with 0x22584/0x22588, not
entirely sure where I would do that even.

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