From: Maarten Lankhorst Date: Mon, 25 Jun 2018 18:37:57 +0200 Subject: drm/i915: Block enabling FBC until flips have been completed MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Git-commit: c9855a561afa5b21db7f2218f0b7baaa555fa90c Patch-mainline: v4.19-rc1 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 There is a small race window in which FBC can be enabled after pre_plane_update is called, but before the page flip has been queued or completed. Signed-off-by: Maarten Lankhorst Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103167 Link: https://patchwork.freedesktop.org/patch/msgid/20180625163758.10871-1-maarten.lankhorst@linux.intel.com Reviewed-by: Ville Syrjälä Acked-by: Petr Tesarik --- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/intel_fbc.c | 35 +++++++++++------------------------ 2 files changed, 12 insertions(+), 24 deletions(-) --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -511,6 +511,7 @@ struct intel_fbc { bool enabled; bool active; + bool flip_pending; bool underrun_detected; struct work_struct underrun_work; --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -924,13 +924,6 @@ static void intel_fbc_get_reg_params(str 32 * fbc->threshold) * 8; } -static bool intel_fbc_reg_params_equal(struct intel_fbc_reg_params *params1, - struct intel_fbc_reg_params *params2) -{ - /* We can use this since intel_fbc_get_reg_params() does a memset. */ - return memcmp(params1, params2, sizeof(*params1)) == 0; -} - void intel_fbc_pre_update(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state, struct intel_plane_state *plane_state) @@ -953,6 +946,7 @@ void intel_fbc_pre_update(struct intel_c goto unlock; intel_fbc_update_state_cache(crtc, crtc_state, plane_state); + fbc->flip_pending = true; deactivate: intel_fbc_deactivate(dev_priv, reason); @@ -988,13 +982,15 @@ static void __intel_fbc_post_update(stru { struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); struct intel_fbc *fbc = &dev_priv->fbc; - struct intel_fbc_reg_params old_params; WARN_ON(!mutex_is_locked(&fbc->lock)); if (!fbc->enabled || fbc->crtc != crtc) return; + fbc->flip_pending = false; + WARN_ON(fbc->active); + if (!i915_modparams.enable_fbc) { intel_fbc_deactivate(dev_priv, "disabled at runtime per module param"); __intel_fbc_disable(dev_priv); @@ -1002,25 +998,16 @@ static void __intel_fbc_post_update(stru return; } - if (!intel_fbc_can_activate(crtc)) { - WARN_ON(fbc->active); - return; - } - - old_params = fbc->params; intel_fbc_get_reg_params(crtc, &fbc->params); - /* If the scanout has not changed, don't modify the FBC settings. - * Note that we make the fundamental assumption that the fb->obj - * cannot be unpinned (and have its GTT offset and fence revoked) - * without first being decoupled from the scanout and FBC disabled. - */ - if (fbc->active && - intel_fbc_reg_params_equal(&old_params, &fbc->params)) + if (!intel_fbc_can_activate(crtc)) return; - intel_fbc_deactivate(dev_priv, "FBC enabled (active or scheduled)"); - intel_fbc_schedule_activation(crtc); + if (!fbc->busy_bits) { + intel_fbc_deactivate(dev_priv, "FBC enabled (active or scheduled)"); + intel_fbc_schedule_activation(crtc); + } else + intel_fbc_deactivate(dev_priv, "frontbuffer write"); } void intel_fbc_post_update(struct intel_crtc *crtc) @@ -1085,7 +1072,7 @@ void intel_fbc_flush(struct drm_i915_pri (frontbuffer_bits & intel_fbc_get_frontbuffer_bit(fbc))) { if (fbc->active) intel_fbc_recompress(dev_priv); - else + else if (!fbc->flip_pending) __intel_fbc_post_update(fbc->crtc); }