From ae662d31264979e52581bd2573bf0b82812f52ab Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Tue, 3 Jan 2012 09:23:29 -0800 Subject: drm/i915: Add support for resetting the SO write pointers on gen7. These registers are automatically incremented by the hardware during transform feedback to track where the next streamed vertex output should go. Unlike the previous generation, which had a packet for setting the corresponding registers to a defined value, gen7 only has MI_LOAD_REGISTER_IMM to do so. That's a secure packet (since it loads an arbitrary register), so we need to do it from the kernel, and it needs to be settable atomically with the batchbuffer execution so that two clients doing transform feedback don't stomp on each others' state. Instead of building a more complicated interface involcing setting the registers to a specific value, just set them to 0 when asked and userland can tweak its pointers accordingly. Signed-off-by: Eric Anholt Reviewed-by: Eugeni Dodonov Reviewed-by: Kenneth Graunke Signed-off-by: Keith Packard --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 31 ++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'drivers/gpu/drm/i915/i915_gem_execbuffer.c') diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 11545ff..c01cb20 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -971,6 +971,31 @@ i915_gem_execbuffer_retire_commands(struct drm_device *dev, } static int +i915_reset_gen7_sol_offsets(struct drm_device *dev, + struct intel_ring_buffer *ring) +{ + drm_i915_private_t *dev_priv = dev->dev_private; + int ret, i; + + if (!IS_GEN7(dev) || ring != &dev_priv->ring[RCS]) + return 0; + + ret = intel_ring_begin(ring, 4 * 3); + if (ret) + return ret; + + for (i = 0; i < 4; i++) { + intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1)); + intel_ring_emit(ring, GEN7_SO_WRITE_OFFSET(i)); + intel_ring_emit(ring, 0); + } + + intel_ring_advance(ring); + + return 0; +} + +static int i915_gem_do_execbuffer(struct drm_device *dev, void *data, struct drm_file *file, struct drm_i915_gem_execbuffer2 *args, @@ -1184,6 +1209,12 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data, dev_priv->relative_constants_mode = mode; } + if (args->flags & I915_EXEC_GEN7_SOL_RESET) { + ret = i915_reset_gen7_sol_offsets(dev, ring); + if (ret) + goto err; + } + trace_i915_gem_ring_dispatch(ring, seqno); exec_start = batch_obj->gtt_offset + args->batch_start_offset; -- cgit v1.1