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

[Russell King - ARM Linux]

On Tue, Oct 31, 2017 at 09:11:37AM +0000, Luís Mendes wrote:
> Hi,
> 
> Russel: I believe that the video corruption I saw with copyNToN(...)
> function of xf86-video-armada is not the root cause of the problem, but
> rather a side effect of the MMU faults.
> Can you help me setup a debug environment where I can dump the client
> process stack from the etnaviv kernel module upon a MMU fault? I have
> enough space on my SSD drive to dump the memory images.

I haven't looked at the kernel etnaviv driver in detail for a while,
but I added support for devcoredump to the driver, which dumps all
buffers attached to the GPU.  This is rigged up to recover_worker().

When a MMU exception occurs, you'd need to call a worker to take
gpu->lock, and then call etnaviv_core_dump() in the same way
recover_worker() does.

You'll need to clone and install

  git://git.armlinux.org.uk/~rmk/etna-gpu-tools.git/

which contains the udev rules to detect when an etnaviv coredump
happens, and automatically unpack it.  It'll want the etna_viv
source for some of the tools, and you'll need to edit the
Makefile to point it to that (it currently uses /shared/etna_viv).

The devcoredump files will be located (by default) in /var/crash,
named etnaviv-$date.bin, and the unpacked versions in
/tmp/etnaviv-$date.

Located in the package are tools to diff between two command
streams, detile etnaviv buffers, a replacement viv_info utility
for the DRM etnaviv version, and some scripts to help hexdump
the MMU and 3D GPU index buffers.

What I've omitted from it is the perl script I use to parse the
GPU command stream - I forget why, but probably because it was
rather dirty, and accessed memory via /dev/mem.  I also don't
think it had the bits for the 2D GPU.  I'll see if I can clean
it up at some point and include it in the above git tree.

-- 
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