[Intel-gfx] [PATCH 8/8] drm/i915: Keep track of reserved execlist ports

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Quoting Mika Kuoppala (2017-09-12 09:36:18)
>> +static inline unsigned int
>> +execlist_active_ports(const struct intel_engine_execlist * const el)
>>  {
>> -       const unsigned int i = port_index(port, el);
>> +       return READ_ONCE(el->port_count);
>
> READ_ONCE? Could we separate the racy check from the serialized uses
> inside the tasklet where we do want the compiler to go to town?

Hmm so substitute execlist_active_ports() in i915_irq.c with
READ_ONCE(el->port_count) and remove it in this function?

-Mika

> -Chris