On Fri, Nov 21, 2014 at 01:39:55AM -0500, Ilia Mirkin wrote: > On Fri, Nov 21, 2014 at 1:16 AM, Andy Ritger <arit...@nvidia.com> wrote: > > Hi Ilia, > > > > Actually 0x90b8 is different than copy engine. I'm not very familiar > > with it, but 0x90b8 is an engine for performing LZO decompression as > > part of performing the copy. It has a variety of limitations (e.g., > > cannot handle blocklinear format), and was only in a few Fermi chips, > > as I understand it. > > According to our driver source, GF100, GF104, GF110, GF114, and GF116 > all have it. [So GF106, GF108, GF117, GF119 don't have it.] We've only > had problems reported against GF116... and only for some people.
Hmm, some of our internal documentation is inconsistent about whether it applies to GF100, but otherwise what I see matches your list. I guess "few" was not entirely accurate. > > It is probably easiest to just ignore it. You can distinguish this > > decompress engine from normal copy engine by looking at the CE capability > > register on falcon (0x00000650). If bit 2 is '1', then the falcon is > > a decompress engine. > > I presume you mean a +0x650 register on the pcopy engines (0x104000 > and 0x105000). I only have access to the GF108 right now, which > returns 3 for 0x104650 and 4 for 0x105650. We're using the engine at > 0x104000 for copy on the GF108... Yes, 0x104650 and 0x105650 are the right addresses, from what I can tell. FWIW, the other capability bits are: bit 0: "DMACOPY_SUPPORTED" bit 1: "PIXREMAP_SUPPORTED" (I think PIXREMAP_SUPPORTED is in reference to the component remapping controlled by methods 0x00000700, 0x00000704, and 0x00000708 in the copy engine class). > From my admittedly limited understanding, both 0x104000 and 0x105000 > appear to be falcon engines, where the fuc is presumably able to drive > some underlying hardware. The actual fifo methods are implemented in > the fuc, which in turn does iowr/etc commands. > > Are you saying that the "decompress" engine (at 0x105000 right?) has a > different piece of hardware behind it than the copy engine at > 0x104000, or does NVIDIA simply provide different fuc for it that > exposes somewhat different functionality via FIFO methods? There is definitely a falcon at the frontend, and there is different falcon ucode for "normal" copy engine versus the "decompress" engine. But, I don't know off hand what dedicated hardware, if any, is behind it. - Andy > > > > I hope that helps, > > - Andy > > > > > > On Thu, Nov 20, 2014 at 02:18:02PM -0500, Ilia Mirkin wrote: > >> Hello, > >> > >> There's a long-standing bug on nouveau (this is a sample bug, but the > >> issue has been around for a while: > >> https://bugs.freedesktop.org/show_bug.cgi?id=85465) whereby we attempt > >> to use the second PCOPY engine on GF116, and it is sometimes does > >> nothing, despite mmio register 22500 saying that it's not disabled > >> (0x22500 == 0 for this user). In the bug you can see a dump from > >> 22400..22600, and all values after 22440 are read as 0. The issue > >> appears to be more common on mobile GF116's, but I don't know that the > >> correlation is 100%. No errors are reported by the FIFO or invalid > >> mmio reads, but the data transfer just does not happen. Switching to > >> using the first copy engine resolves things, so it's unlikely to be a > >> more systemic issue in nouveau's usage of the copy engine. > >> > >> To be clear, when I'm talking about the second PCOPY engine, I'm > >> talking about the engine at mmio 0x105000, and whose fifo class id is > >> 0x90b8. > >> > >> Any information on properly detecting that the engine is, in fact, > >> missing, would be greatly appreciated. Or, conversely, an assurance > >> that the engine _is_ there on all GF116's and we're just not > >> initializing something properly, along with perhaps some suggestions > >> as to what we might be missing. > >> > >> Thanks, > >> > >> Ilia Mirkin > >> imir...@alum.mit.edu > >> _______________________________________________ > >> Nouveau mailing list > >> Nouveau@lists.freedesktop.org > >> http://lists.freedesktop.org/mailman/listinfo/nouveau _______________________________________________ Nouveau mailing list Nouveau@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/nouveau
