[Nouveau] NV50 compute support questions

[Hans de Goede]

Hi,

On 02-12-15 19:33, Samuel Pitoiset wrote:
>
>
> On 12/02/2015 04:34 PM, Hans de Goede wrote:
>> On 01-12-15, Samuel Pitoiset wrote:
>>
>>  >>> Ok, here is a MMT trace of vectorAdd:
>>  >>>
>>  >>> https://fedorapeople.org/~jwrdegoede/vectorAdd.log.gz
>>  >>
>>  >> Hi Hans,
>>  >>
>>  >> Thanks a lot.
>>  >
>>  > Well, I didn't know but Martin has a GK208...
>>  > I just tested the compute support on his card and ... it works without
>>  > any changes. :-)
>>  >
>>  > I'm sorry, I was sure the compute support didn't work on this chipset.
>>
>> No need to be sorry because, ...
>>
>>  > Feel free to test on your GK208 and report back if you have problems.
>>
>> I've done that, and for me it does not work, if I try to enable compute
>> support like this:
>>
>> diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> index 461fcaa..ab4ea85 100644
>> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> @@ -187,7 +187,7 @@ nvc0_screen_get_param(struct pipe_screen *pscreen,
>> enum pipe_cap param)
>>      case PIPE_CAP_SEAMLESS_CUBE_MAP_PER_TEXTURE:
>>         return (class_3d >= NVE4_3D_CLASS) ? 1 : 0;
>>      case PIPE_CAP_COMPUTE:
>> -      return (class_3d <= NVE4_3D_CLASS) ? 1 : 0;
>> +      return 1;
>>      case PIPE_CAP_PREFER_BLIT_BASED_TEXTURE_TRANSFER:
>>         return nouveau_screen(pscreen)->vram_domain & NOUVEAU_BO_VRAM ?
>> 1 : 0;
>>
>> @@ -246,8 +246,6 @@ nvc0_screen_get_shader_param(struct pipe_screen
>> *pscreen, unsigned shader,
>>            return 0;
>>         break;
>>      case PIPE_SHADER_COMPUTE:
>> -      if (class_3d > NVE4_3D_CLASS)
>> -         return 0;
>>         break;
>>      default:
>>         return 0;
>> @@ -574,11 +572,10 @@ nvc0_screen_init_compute(struct nvc0_screen *screen)
>>      case 0xd0:
>>         return nvc0_screen_compute_setup(screen, screen->base.pushbuf);
>>      case 0xe0:
>> -      return nve4_screen_compute_setup(screen, screen->base.pushbuf);
>>      case 0xf0:
>>      case 0x100:
>>      case 0x110:
>> -      return 0;
>> +      return nve4_screen_compute_setup(screen, screen->base.pushbuf);
>>      default:
>>         return -1;
>>      }
>>
>> Then as soon as I do startx (which starts gnome-shell) the machine
>> freezes. This is with mesa-master with the above changes on top.
>>
>> X / gnome-shell will happily work of I do not call
>> nve4_screen_compute_setup()
>> but then test/trivial/compute fails with a null-ptr exception.
>>
>> Do you perhaps have some extra patches in your tree, or am I just unlucky ?
>>
>> I've tested this on both a 4.2 and a 4.4-rc3 kernel.
>
> Hi,
>
> My bad... I used the wrong card on reator (which is the REing machine of Martin). The primary card is a GK106 and the second one is the GK208. That doesn't explain why I did something wrong but heh? :-)
>
> You are right. With those bits added locally, the compute support totally hangs the GPU on my GK208 (NV108), and a reboot is needed.
>
> Please give a shot at this branch :
> http://cgit.freedesktop.org/~hakzsam/mesa/log/?h=nvf0_compute
>
> It fixes the initialization of the compute state and allows me to
> launch 'test_input_global' (ie. ./compute 8) on my GK208 without
> any dmesg fails. That's a good start but more patches are coming. :-)

This branch indeed works somewhat better, but things still hang on the

test_system_values compute test for me (this is the first test executed
I did not try the others). So this seems to need more work.

I've ordered a GTX740 (GK107) card, which should arrive soon, and
I'll be using that so I can (hopefully) focus on the llvm tgsi bits
again.

> Btw, according to the trace you sent me, you have a GK208b (NV106).

Right, sorry I thought the differences between GK208 and GK208b would not matter.

Thanks for all the input / help!

Regards,

Hans