GC300 2D unit won't work with GC2000 3D disabled on MMP3

[Lubomir Rintel]

On Tue, Dec 01, 2020 at 11:33:36AM +0100, Lucas Stach wrote:
> Hi Lubomir,
> 
> Am Montag, den 30.11.2020, 18:07 +0100 schrieb Lubomir Rintel:
>> Hello,
>> 
>> (adding Ivan to Cc, since he brought the issue up privately. Ivan,
>> etnaviv@ is a moderated list, please subscribe if you're going to
>> reply.)
>> 
>> I'm wondering if anyone can help me understand what is going with
>> Vivante
>> GC300 on a MMP3 and find a reasonable fix. MMP3 has these two GPU
>> cores:
>> 
>>   [    2.142545] etnaviv-gpu d420d000.gpu: model: GC2000, revision:
>> 5026
>>   [    2.154468] etnaviv-gpu d420f000.gpu: model: GC300, revision: 4634
>>   [    2.166808] [drm] Initialized etnaviv 1.3.0 20151214 for etnaviv
>> on minor 0
>> 
>> Currently, clients that try to use the GC300 2D unit -- libdrm's
>> etnaviv_2d
>> test or the xorg-x11-drv-armada ddx on a MMP3 don't work and etnaviv
>> complains:
>> 
>>   [  295.077770] etnaviv-gpu d420d000.gpu: recover hung GPU!
>> 
>> That is, until the clock that's supposedly for the GC2000 3D unit are
>> turned on. Then things work fine.
> 
> I believe the above splat is with the etnaviv_2d_test? This test is
> broken in that it will just pick the first GPU core (in your case the
> GC2000) instead of looking for a core with 2D capabilities. Submitting
> 2D jobs into the 3D GPU will do nothing or hang the GPU, depending on
> the specific GPU generation.

Yes,

With core=0 the output is:

  etnaviv-gpu d420d000.gpu: recover hung GPU!

If I change the test to set core=1, I get two extra lines:

  etnaviv-gpu d420f000.gpu: recover hung GPU!
  etnaviv-gpu d420f000.gpu: GPU failed to reset: FE not idle, 3D not idle, 2D not idle
  etnaviv-gpu d420f000.gpu: GPU not yet idle, mask: 0x00000000

> I don't know exactly what the armada driver is doing, IIRC it properly
> looks for a 2D GPU core.

It seems to. It logs this line:

  [  1275.130] (--) armada(0): Vivante GC300 GPU revision 4634 (etnaviv) 2d PE2.0

The kernel output is:

  etnaviv-gpu d420f000.gpu: recover hung GPU!
  etnaviv-gpu d420f000.gpu: GPU failed to reset: FE not idle, 3D not idle, 2D not idle
  etnaviv-gpu d420f000.gpu: recover hung GPU!
  etnaviv-gpu d420f000.gpu: GPU failed to reset: FE not idle, 3D not idle, 2D not idle
  etnaviv-gpu d420f000.gpu: recover hung GPU!

> Is the symptom the same if the 2d_test is fixed to submit into the
> right GPU core?

See above.

Note that if I force the clock on the test succeeds (and the result is
correct) with either core=0 or core=1. I don't know if both cores are 2D
capable; I have no idea how to tell. Here the feature words are:

  core=0 ETNA_GPU_FEATURES_0 = 0xe0286cad
  core=0 ETNA_GPU_FEATURES_1 = 0xcb799eff
  core=0 ETNA_GPU_FEATURES_2 = 0x2e13b2d9
  core=0 ETNA_GPU_FEATURES_3 = 0x02000000

  core=1 ETNA_GPU_FEATURES_0 = 0xe02c7eca
  core=1 ETNA_GPU_FEATURES_1 = 0xe1399fff
  core=1 ETNA_GPU_FEATURES_2 = 0x2e13b219
  core=1 ETNA_GPU_FEATURES_3 = 0x00010000

> Regards,
> Lucas

Take care
Lubo