Re: [PATCH 1/2] drm/i915/bdw: Apply workarounds in render ring init function

["Siluvery, Arun" <arun.siluvery@linux.intel.com>]

On 26/08/2014 11:09, Chris Wilson wrote:
> On Tue, Aug 26, 2014 at 10:33:16AM +0100, Arun Siluvery wrote:
>> For BDW workarounds are currently initialized in init_clock_gating() but
>> they are lost during reset, suspend/resume etc; this patch moves the WAs
>> that are part of register state context to render ring init fn otherwise
>> default context ends up with incorrect values as they don't get initialized
>> until init_clock_gating fn.
>>
>> v2: Add workarounds to golden render state
>> This method has its own issues, first of all this is different for
>> each gen and it is generated using a tool so adding new workaround
>> and mainitaining them across gens is not a straightforward process.
>>
>> v3: Use LRIs to emit these workarounds (Ville)
>> Instead of modifying the golden render state the same LRIs are
>> emitted from within the driver.
>>
>> For: VIZ-4092
>> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_gem_context.c |  6 +++
>>   drivers/gpu/drm/i915/intel_pm.c         | 48 --------------------
>>   drivers/gpu/drm/i915/intel_ringbuffer.c | 78 +++++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/i915/intel_ringbuffer.h |  1 +
>>   4 files changed, 85 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
>> index 9683e62..2debce4 100644
>> --- a/drivers/gpu/drm/i915/i915_gem_context.c
>> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
>> @@ -631,20 +631,26 @@ static int do_switch(struct intel_engine_cs *ring,
>>   	}
>>
>>   	uninitialized = !to->legacy_hw_ctx.initialized && from == NULL;
>>   	to->legacy_hw_ctx.initialized = true;
>>
>>   done:
>>   	i915_gem_context_reference(to);
>>   	ring->last_context = to;
>>
>>   	if (uninitialized) {
>> +		if (IS_BROADWELL(ring->dev)) {
>> +			ret = bdw_init_workarounds(ring);
>> +			if (ret)
>> +				DRM_ERROR("init workarounds: %d\n", ret);
>
> A good rule of thumb is that if you are exporting gen specific routines,
> the layering and abstraction is fishy.
> -Chris
>
ok, so something like i915_init_workarounds() is ok? with a check for 
bdw/gen8 done inside that function.

regards
Arun