From 9dbd8febb4dbc9199fcf340b882eb930e36b65b6 Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Tue, 23 Jul 2013 10:48:11 -0300 Subject: [PATCH] drm/i915: update last_vblank when disabling the power well The DRM layer keeps track of our vblanks and it assumes our vblank counters only go back to zero when they overflow. The problem is that when we disable the power well our counters also go to zero, but it doesn't mean they did overflow. So on this patch we grab the lock and update last_vblank so the DRM layer won't think our counters overflowed. This patch fixes the following intel-gpu-tools test: ./kms_flip --run-subtest blocking-absolute-wf_vblank Regression introduced by the following commit: commit bf51d5e2cda5d36d98e4b46ac7fca9461e512c41 Author: Paulo Zanoni Date: Wed Jul 3 17:12:13 2013 -0300 drm/i915: switch disable_power_well default value to 1 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66808 Signed-off-by: Paulo Zanoni [danvet: Added a comment that this might be better done in drm_vblank_post_modeset in general.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_pm.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index f895d1508df8..b0e4a0bd1313 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5063,8 +5063,26 @@ static void __intel_set_power_well(struct drm_device *dev, bool enable) } } else { if (enable_requested) { + unsigned long irqflags; + enum pipe p; + I915_WRITE(HSW_PWR_WELL_DRIVER, 0); + POSTING_READ(HSW_PWR_WELL_DRIVER); DRM_DEBUG_KMS("Requesting to disable the power well\n"); + + /* + * After this, the registers on the pipes that are part + * of the power well will become zero, so we have to + * adjust our counters according to that. + * + * FIXME: Should we do this in general in + * drm_vblank_post_modeset? + */ + spin_lock_irqsave(&dev->vbl_lock, irqflags); + for_each_pipe(p) + if (p != PIPE_A) + dev->last_vblank[p] = 0; + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } } }