On Wed, Oct 22, 2014 at 04:28:51PM +0100, Robert Bragg wrote:
> + /* XXX: Not sure that this is really acceptable...
> + *
> + * i915_gem_context.c currently owns pinning/unpinning legacy
> + * context buffers and although that code has a
> + * get_context_alignment() func to handle a different
> + * constraint for gen6 we are assuming it's fixed for gen7
> + * here. Another option besides pinning here would be to
> + * instead hook into context switching and update the
> + * OACONTROL configuration on the fly.
> + */
> + if (dev_priv->oa_pmu.specific_ctx) {
> + struct intel_context *ctx = dev_priv->oa_pmu.specific_ctx;
> + int ret;
> +
> + ret = i915_gem_obj_ggtt_pin(ctx->legacy_hw_ctx.rcs_state,
> + 4096, 0);
Right if you pin it here with a different alignment, when we try to pin
it with the required hw ctx alignment it will fail. Easiest way is to
record the ctx->legacy_hw_ctx.alignment and reuse that here.
> + if (ret) {
> + DRM_DEBUG_DRIVER("Couldn't pin %d\n", ret);
> + ret = -EBUSY;
As an exercise, think of all the possible error values from pin() and
tell me why overriding that here is a bad, bad idea.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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