The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90c702b88e5b5bbe2be53848aa3aba7c2b64223f Mon Sep 17 00:00:00 2001

From: Maarten Lankhorst maarten.lankhorst@linux.intel.com Date: Thu, 19 Oct 2017 17:13:41 +0200 Subject: [PATCH] drm/i915: Calculate ironlake intermediate watermarks correctly, v2. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

The watermarks it should calculate against are the old optimal watermarks. The currently active crtc watermarks are pure fiction, and are invalid in case of a nonblocking modeset, page flip enabling/disabling planes or any other reason.

When the crtc is disabled or during a modeset the intermediate watermarks don't need to be programmed separately, and could be directly assigned to the optimal watermarks.

Changes since v1: - Use intel_atomic_get_old_crtc_state. (ville)

Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Reviewed-by: Matt Roper matthew.d.roper@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20171019151341.4579-2-maarten.... [mlankhorst: Add cc stable and bugzilla link, since previous patch doesn't fix issue by itself] Cc: stable@vger.kernel.org #v4.8+ Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102373 (cherry picked from commit b6b178a77210055b153dbc175e4468bd3c7122df) Signed-off-by: Jani Nikula jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index c42a65a93b3a..7d2ecabc5de5 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3133,7 +3133,11 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev, struct intel_crtc_state *newstate) { struct intel_pipe_wm *a = &newstate->wm.ilk.intermediate; - struct intel_pipe_wm *b = &intel_crtc->wm.active.ilk; + struct intel_atomic_state *intel_state = + to_intel_atomic_state(newstate->base.state); + const struct intel_crtc_state *oldstate = + intel_atomic_get_old_crtc_state(intel_state, intel_crtc); + const struct intel_pipe_wm *b = &oldstate->wm.ilk.optimal; int level, max_level = ilk_wm_max_level(to_i915(dev));

/* @@ -3142,6 +3146,9 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev, * and after the vblank. */ *a = newstate->wm.ilk.optimal; + if (!newstate->base.active || drm_atomic_crtc_needs_modeset(&newstate->base)) + return 0; + a->pipe_enabled |= b->pipe_enabled; a->sprites_enabled |= b->sprites_enabled; a->sprites_scaled |= b->sprites_scaled;