On 18/04/17 02:04 PM, Ilia Mirkin wrote: > On Mon, Apr 17, 2017 at 10:53 PM, Michel Dänzer <michel at daenzer.net> wrote: >> On 17/04/17 03:43 PM, Ilia Mirkin wrote: >>> On Tue, Apr 11, 2017 at 10:18 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote: >>>>> However, I totally agree with Alex that someone with a BE machine >>>>> should review the whole stack before we could be confident with anything. >>>> >>>> Here's what I'm confident about: xf86-video-nouveau worked just fine >>>> on top of kernel 4.3 on an AGP GeForce FX 5200 (with AGPGART turned >>>> off because ... well ... uninorth). fbcon/fbdev accel worked, >>>> xf86-video-nouveau's 2d accel worked, and simple demos (ala glxgears) >>>> worked after I fixed up mesa and nv30 driver items in version ... 11.1 >>>> it seems. As I recall it had gotten all broken in 10.0 or so by Adam >>>> Jackson in the name of making llvmpipe work on BE, declaring all other >>>> drivers broken, with various fixes by Michel Dänzer to get it back to >>>> working over the years. >>>> >>>> Anyone "fixing" the stack has to maintain that level of functioning >>>> through their various fixing. >>>> >>>> I will double-check that the above still works with the latest >>>> kernel/xorg/xf86-video-nouveau/mesa and report back (hopefully by this >>>> weekend). If there are any patches you'd like me to test, now's the >>>> time to ask -- getting the box up and running is the hard part, >>>> booting up an extra kernel -- easy. >>> >>> OK, so I revived my PowerMac7,3 G5 setup (PPC64 BE, NV34 GPU). Booted >>> it with an upstream 4.11-rc7 kernel, loaded up the nouveau kernel >>> module (which is included in that kernel), updated X to 1.19.2 and >>> mesa to 17.0.3. Everything works fine. Specifically: >>> >>> fbcon on top of fbdev provided by nouveau -- colors are fine >>> glxgears hw-accelerated by mesa on top of xf86-video-nouveau using >>> DRI2 -- colors are fine >>> glxgears softpipe-accelerated by mesa on top of xf86-video-nouveau -- >>> colors are fine >>> glxgears softpipe-accelerated by mesa on top of xf86-video-modesetting >>> -- colors are fine >>> xterm on top of xf86-video-nouveau -- colors are fine >>> xterm on top of xf86-video-modesetting -- colors are fine >>> >>> I couldn't test anything with GLAMOR since GLAMOR requires GL 2.1 or >>> higher, whereas nouveau's NV3x acceleration only provides GL 1.5 (due >>> to lacking NPOT and a handful of other things). >>> >>> The modetest utility did have trouble with AR24 and I'm pretty sure >>> the XR24 pattern was off too. However I wouldn't be surprised if the >>> modetest utility itself had endian issues in the pattern generation >>> logic. (Seems to be the case, based on a quick glance at the >>> tests/util/format.c logic and how it's used in pattern.c.) >>> >>> So in short, I think the current definitions of format are fine. >> >> I agree with Pekka that it's not that simple. What you've established is >> that things look fine after going through several layers of abstraction. >> It's possible that multiple bugs in those layers cancel each other out; >> in particular, it's quite likely that the code dealing with DRM formats >> is treating them as using native endianness (one possible giveaway for >> that is using shifts for (un)packing colour components). > > Quite true that this proves nothing. However one should note that > fbcon -> fbdev works, BTW, this supports Gerd's patch, since the KMS fbdev emulation code uses e.g. DRM_FORMAT_XRGB8888 for depth/bpp 24/32, and the fbdev API uses native endian packed colour values. > and both mesa hw driver and softpipe driver work, in addition to regular > DDX accel. Similarly, the X11 protocol uses native endian packed colour values. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
