From: Daniel Vetter Date: Wed, 4 Aug 2010 19:22:10 +0000 (+0200) Subject: drm/i915: i8xx also doesn't like multiple oustanding pageflips X-Git-Tag: v2.6.36-rc2~2^2~44 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6146b3d61925116e3fecce36c2fd873665bd6614;p=karo-tx-linux.git 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 --- 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;