From ab28a5474a497d201091ba20ca9c33260bb2b2af Mon Sep 17 00:00:00 2001 From: Paulo Zanoni Date: Mon, 4 Apr 2016 18:17:15 -0300 Subject: [PATCH] drm/i915/fbc: update busy_bits even for GTT and flip flushes We ignore ORIGIN_GTT because the hardware tracking can recognize GTT writes and take care of them. We also ignore ORIGIN_FLIP because we deal with flips without relying on the frontbuffer tracking infrastructure. On the other hand, a flush is a flush and means we're good to go, so we need to update busy_bits in order to reflect that, even if we're not going to do anything else about it. How to reproduce the bug fixed by this patch: - boot SKL up to the desktop environment - stop the display manager - run any of the igt/kms_frontbuffer_tracking/*fbc*onoff* subtests - the tests will fail The steps above will create the right conditions for us to lose track of busy_bits. If you, for example, run the full set of FBC tests, the onoff subtests will succeed. Also notice that the "bug" is that we'll just keep FBC disabled on cases where it could be enabled, so it's not something the users can perceive, it just affects power consumption numbers on properly configured machines. Testcase: igt/kms_frontbuffer_tracking/*fbc*onoff* (see above) Reviewed-by: Daniel Vetter Signed-off-by: Paulo Zanoni Link: http://patchwork.freedesktop.org/patch/msgid/1459804638-3588-2-git-send-email-paulo.r.zanoni@intel.com --- drivers/gpu/drm/i915/intel_fbc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c index a19944b6dc25..e43c867490e5 100644 --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -992,13 +992,13 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv, if (!fbc_supported(dev_priv)) return; - if (origin == ORIGIN_GTT || origin == ORIGIN_FLIP) - return; - mutex_lock(&fbc->lock); fbc->busy_bits &= ~frontbuffer_bits; + if (origin == ORIGIN_GTT || origin == ORIGIN_FLIP) + goto out; + if (!fbc->busy_bits && fbc->enabled && (frontbuffer_bits & intel_fbc_get_frontbuffer_bit(fbc))) { if (fbc->active) @@ -1007,6 +1007,7 @@ void intel_fbc_flush(struct drm_i915_private *dev_priv, __intel_fbc_post_update(fbc->crtc); } +out: mutex_unlock(&fbc->lock); } -- GitLab