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

[Lucas Stach]

Am Dienstag, den 01.12.2020, 14:49 +0100 schrieb 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

Okay, this looks at least somewhat like what I would expect with a
missing clock.

As GPU cores are normally fully independent, I guess your understanding
of the clock tree in the SoC isn't fully correct. Is it possible that
GC3D_AXICLK_EN really is a clock source for both the 2D and 3D GPU core
AXI interfaces?

> > 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.

So you get the green rectangles in the picture even with core=0? That
would be very unexpected.

>  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

2D pipe is bit 9 in the FEATURE_0 register, so only the 2nd core claims
to support 2D commands, as expected.

Regards,
Lucas