[Intel-gfx] [PATCH v6 08/11] drm/i915: add a new perf configuration execbuf parameter

[Lionel Landwerlin]

On 01/07/2019 15:05, Chris Wilson wrote:
> Quoting Lionel Landwerlin (2019-07-01 12:34:34)
>> +static int eb_oa_config(struct i915_execbuffer *eb)
>> +{
>> +       int err;
>> +
>> +       if (!eb->oa_config)
>> +               return 0;
>> +
>> +       err = i915_active_request_set(&eb->engine->last_oa_config,
>> +                                     eb->request);
>> +       if (err)
>> +               return err;
>> +
>> +       /*
>> +        * If the config hasn't changed, skip reconfiguring the HW (this is
>> +        * subject to a delay we want to avoid has much as possible).
>> +        */
>> +       if (eb->oa_config == eb->i915->perf.oa.exclusive_stream->oa_config)
>> +               return 0;
> So what's the story for resets? I presume the OA config is lost on a
> device reset, and possible an engine reset? If so, then if we reset, we
> lose the config and do not notice.
> -Chris
>
The current story (before those patches) for resets and OA is already 
pretty undefined.

I haven't actually gone to look at all the OA register see what they 
reset value would be.


At the moment we should consider a reset to make your results invalid.

I'll try to dig a bit on this.


-Lionel