radeon CS parser refactoring

[Ilija Hadzic]

On Fri, 4 Jan 2013, Dave Airlie wrote:

> Did you run these with pre-kms userspace etc to make sure it doesn't
> cause regressions there?
>

I did some tests with UMS and shuffled a number of cards. As I feared, I 
ran into a number of unrelated problems, but in each case I have seen 
identical beahvior between the kernel with my patches and without. So as 
far as I can tell, my patches do not introduce regressions in legacy 
modes, althugh I am not sure about the coverage.

Also, in one test, I think I have hit a genuine bug in ATI DDX (explained 
below).

Below I describe what I saw with each card family. Maybe for some test 
cases I am missing some "magic" option in xorg.conf or maybe what I am 
seeing (mostly reduced feature set) is expected in UMS.

* With an NI card (TURKS, HD6570 card), Xorg just plain tells me that the
   card is supported in KMS only mode. So, I guess, that's it for that
   card.

* A test with Evergreen (CEDAR) card works in UMS mode, but I can't
   get 3D acceleration. I see these messages in Xorg log file:

[    37.024] (II) RADEON(0): No DRI yet on Evergreen
.....
.....
[    37.364] (II) AIGLX: Screen 0 is not DRI2 capable
[    37.364] (II) AIGLX: Screen 0 is not DRI capable
[    37.664] (II) AIGLX: Loaded and initialized swrast
[    37.664] (II) GLX: Initialized DRISWRAST GL provider for screen 0

   Sounds like just a "property" of UMS to me, but I am not sure.
   Nevertheless, the behavior with and without my kernel patches is
   identical. Still, 2D copying should still be exercising the CS
   parser, so there is some test coverage here.

* A test with an R7xx card (RV730, E4690 card) results in a segfault in
   DDX. Again, this is irrespective of my kernel patches, so I believe
   that the bug has been there for a while and that it's in userland.
   The crash occurs in r600_set_render_target() function and what causes
   it is corrupted cb_conf->surface pointer. When the crash occurs it
   has a value of 0x1, which doesn't look like something that would live
   in .bss, .data or come from the heap. I didn't try other R6xx cards,
   but I suspect that they may have the same problem because they share
   the code in DDX. I don't know if UMS DDX will be maintained going
   forward, so I don't know if it makes sense to open a bug for this.
   BTW, DDX I am testing this with is 6.14.6

* A test with R300 card (Radeon X300 card) works (again identically
   with and without my patches), but again without 3D acceleration.
   So it's similar result and comment as with the Evergreen test, though
   relevant messages in Xorg log file are slightly different:

[    35.630] (EE) AIGLX error: r300 does not export required DRI extension
[    35.630] (EE) AIGLX: reverting to software rendering
[    35.915] (II) AIGLX: Loaded and initialized swrast
[    35.915] (II) GLX: Initialized DRISWRAST GL provider for screen 0

   Again, I don't know if this is just the way things are in UMS mode or if
   there is some configuration magic I need to do.

So at this point I'd say that I have not seen anything that would indicate 
a regression in legacy mode, although the limitations I have hit make the 
tests more limited that I thought they would be (and KMS I tested quite a 
bit, so I am confident there).

thanks,

Ilija