Re: [PATCH i-g-t 1/3] igt/gem_cpu_reloc: Check HW exists before attempting to use it

[Antonio Argenziano <antonio.argenziano@intel.com>]

On 17/05/18 09:52, Chris Wilson wrote:
> Quoting Antonio Argenziano (2018-05-17 17:29:26)
>>
>>
>> On 17/05/18 08:37, Chris Wilson wrote:
>>> Quoting Antonio Argenziano (2018-05-17 16:08:14)
>>>>
>>>>
>>>> On 17/05/18 01:23, Chris Wilson wrote:
>>>>> Confirm we have the available HW before asserting it succeeds.
>>>>>
>>>>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>>>>> ---
>>>>>     tests/gem_cpu_reloc.c | 1 +
>>>>>     1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/tests/gem_cpu_reloc.c b/tests/gem_cpu_reloc.c
>>>>> index 882c312d4..e3bbcd239 100644
>>>>> --- a/tests/gem_cpu_reloc.c
>>>>> +++ b/tests/gem_cpu_reloc.c
>>>>> @@ -167,6 +167,7 @@ static void run_test(int fd, int count)
>>>>>         use_blt = 0;
>>>>
>>>> Is this^ meant to be EXEC_DEFAULT?
>>>
>>> Depends on your viewpoint. EXEC_DEFAULT is zero.
>>
>> Just wandering if it should enforce EXEC_RENDER. Which I think is what
>> we want for gen 5-.
> 
> Not really. It just wants the default mixed ring. You definitely don't
> want to suggest sending blitter commands down the 3D pipe, that would be
> even more confusing.

The comment below answers this question as well.

> 
>>>>>         if (intel_gen(noop) >= 6)
>>>>>                 use_blt = I915_EXEC_BLT;
>>>>> +     gem_require_ring(fd, use_blt);
>>>>
>>>> Are any gens 6+ that do not have a BLT ring? if that is the case
>>>> shouldn't we use '0' like we do for 5- gens?
>>>
>>> No, it has to match the engine for which the blitter commands are valid. If
>>> that engine does not exist, there is no alternative except to rewrite the
>>> test not to use those commands. If there was, it indeed would be included
>>> in the selection above.
>>
>> So, just to wrap my head around it, the commands we are talking about
>> here are allowed on render for gen5- but only on blitter on 6+. Right?
> 
> There is no render for gen5- either. There is a universal ringbuffer
> that can handle multiple different client commands, and on the odd
> machine a bit stream decoder.

I see, I wasn't making any sense then :).

Reviewed-by: Antonio Argenziano <antonio.argenziano@intel.com>

> -Chris
> 
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx