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

[Chris Wilson]

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 at 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

-- 
Chris Wilson, Intel Open Source Technology Centre