etnaviv-gpu 134000.gpu: MMU fault status 0x00000002 on i.XM6 Quad Plus

[Lucas Stach]

Am Donnerstag, den 31.08.2017, 13:36 +0100 schrieb Luís Mendes:



> The imx6q is not showing any issues on this Ubuntu Mate 17.04, even
> for the conditions:
> Aug 31 11:58:08 picolo etnaviv[4694]: Mismatch src(y=0,h=24),
> dst(y=0,h=25), dy=0
> Aug 31 11:58:08 picolo etnaviv[4694]: Mismatch src(y=0,h=24),
> dst(y=-25,h=25), dy=25
> Aug 31 11:58:08 picolo etnaviv[4694]: Mismatch src(y=0,h=1),
> dst(y=-25,h=25), dy=1
> Aug 31 11:58:12 picolo etnaviv[4694]: Mismatch src(y=0,h=1),
> dst(y=0,h=25), dy=0
> 
> 
> No MMU faults, no screen corruptions.
> 

The GPUs on MY6Q are unable to produce MMU faults, so with incorrect
programming they are reading/writing unrelated data, or the MMU scratch
page.


> The imx6qp always have MMU faults and is showing the issues when
> removing the "goto callback" instruction.
> Aug 30 18:41:32 picolo etnaviv[1722]: Mismatch src(y=0,h=24),
> dst(y=0,h=25), dy=0
> Aug 30 18:41:34 picolo etnaviv[1722]: Mismatch src(y=0,h=24),
> dst(y=-25,h=25), dy=25
> Aug 30 18:41:34 picolo etnaviv[1722]: Mismatch src(y=0,h=1),
> dst(y=-25,h=25), dy=1
> Aug 30 18:41:41 picolo etnaviv[1722]: Mismatch src(y=0,h=1),
> dst(y=0,h=25), dy=0

The MX6QP is much stricter on the MMU side and will stop the GPU from
processing any further commands if it is trying to read/write unmapped
data.

> 
> This probably indicates that there is no implementation issue with
> CopyNtoN and this is rather a side effect of the MMU faults.
> 

This indicates there is in fact an implementation error in CopyNtoN, but
as Russell pointed out it seems to be caused by core X server functions.
The question is if we can reasonably work around the issue.

Regards,
Lucas