Re: [CI 2/2] drm/i915: Initialize legacy semaphores from engine hw id indexed array

Tvrtko Ursulin
2016-08-17T14:36:53Z

On 17/08/16 11:05, Chris Wilson wrote:
> On Wed, Aug 17, 2016 at 10:57:34AM +0100, Tvrtko Ursulin wrote:
>>
>> On 17/08/16 10:41, Chris Wilson wrote:
>>> On Wed, Aug 17, 2016 at 10:34:18AM +0100, Tvrtko Ursulin wrote:
>>>> Or add an initialized engine array to dev_priv, in addition to the
>>>> existing map for best of both worlds.
>>>
>>> We have the ring_mask which already tells us that mapping, so I think
>>> the second array is overkill.
>>
>> Yes, I said "in addition to the existing map". In addition we could
>> have an array of only initialized engines to avoid any skipping at
>> runtime. Since iterators end with intel_engine_initialized anyway.
>
> And I'm saying we already have that information in ring_mask.

The ffs smarts you've been developing? I am not sure devising very smart
macros and expanding all that code to all the call sites is that great.
It is effectively just re-implementing arrays at runtime using CPU
instructions.

What would be the big deal of just building the array when engines are
initialized for simplicity? Just the allure of getting away with no
iterator variable?

Regards,

Tvrtko