From 6146b3d61925116e3fecce36c2fd873665bd6614 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 4 Aug 2010 21:22:10 +0200 Subject: [PATCH] drm/i915: i8xx also doesn't like multiple oustanding pageflips My i855GM suffers from a 80k/s interrupt storm without this. So add 2nd gen to the list of things that don't like more than one outstanding pageflip request. Furthermore I've changed the busy loop into a ringbuffer wait. Busy-loops that don't check whether the chip died are simply evil. And performance should actually improve, because there's usually a decent amount of rendering queued on the gpu, hopefully rendering that MI_WAIT into a noop by the time it's executed. The current code holds dev->struct_mutex while executing this loop, hence stalling all other gem activity anyway. Signed-off-by: Daniel Vetter Cc: stable@kernel.org Reviewed-by: Jesse Barnes [anholt: resolved against conflict] Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/intel_display.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index ce7a46b6909b..22966bd9aa96 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -5098,14 +5098,16 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, work->pending_flip_obj = obj; if (intel_crtc->plane) - flip_mask = I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT; + flip_mask = MI_WAIT_FOR_PLANE_B_FLIP; else - flip_mask = I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT; + flip_mask = MI_WAIT_FOR_PLANE_A_FLIP; - /* Wait for any previous flip to finish */ - if (IS_GEN3(dev)) - while (I915_READ(ISR) & flip_mask) - ; + if (IS_GEN3(dev) || IS_GEN2(dev)) { + BEGIN_LP_RING(2); + OUT_RING(MI_WAIT_FOR_EVENT | flip_mask); + OUT_RING(0); + ADVANCE_LP_RING(); + } /* Offset into the new buffer for cases of shared fbs between CRTCs */ offset = obj_priv->gtt_offset; -- 2.11.0