Re: GPU lockup dumping

[Jordan Crouse <jcrouse@codeaurora.org>]

On 05/23/2012 08:51 AM, Jerome Glisse wrote:
> On Wed, May 23, 2012 at 5:27 AM, Dave Airlie<airlied@gmail.com>  wrote:
>> On Thu, May 17, 2012 at 7:28 PM,<j.glisse@gmail.com>  wrote:
>>> So here is improved patchset, where i splited ground work necessary
>>> for the dumping into their own patch. The debugfs improvement could
>>> probably be usefull to intel instead of having i915 have it's own
>>> debugfs file stuff.
>>>
>>> The lockup dumping public api have been move into radeon_drm.h
>>>
>>> Stressing the fact again that dump are self contained ie they have
>>> all the data needed to be replayed (vertex, indices, shader, texture,
>>> ...).
>>>
>>> Would really like to get this into 3.5, the new API is pretty much
>>> straightforward and userspace tools can easily be made to convert
>>> it to other format. The change to the driver is self contained.
>>
>> I really don't like introducing this at this stage into 3.5,
>>
>> I'd really like a good review of the API and what information we provide
>> along with how extensible it is.
>>
>> I'm still not convinced replay is what we want in the field, I know its what
>> *you* want, but I think apitrace stuff in userspace pretty much covers
>> the replaying situation. So I'd have to look at this and see how easy
>> it makes disecting command streams etc.
>>
>> Dave.
>
> It store pciid and allow to dump all ib per ring, and all associated
> bo object. It also have a bunch of flags to help the userspace tools
> (like does userspace need to clear offset (vm vs no vm) ...  What more
> do you want to know ?

Another useful thing might be current register states. We've been doing
dumping (we call it snapshot) in the Qualcomm driver for a little bit now and
between registers, rings, command buffers and various buffers we've been able
to get a reasonably good picture of the state suitable for playback on emulators
and other silly userspace tricks.

We have structs for registers and index/data register pairs because we also dump
lots of debug registers and queues and other various HW sources.

The implementation is way different for obvious reasons but I would love to
consolidate on a single format. Its easy for us to do since we share similar
architectures, but if  least two GPUs support the same format it can be a catalyst
for others to join.

https://www.codeaurora.org/gitweb/quic/la/?p=kernel/msm.git;a=blob;f=drivers/gpu/msm/kgsl_snapshot.h;hb=refs/heads/msm-3.0

Jordan