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 556fe36d09da5f82879e92bafa0371b4b79f7d6f Mon Sep 17 00:00:00 2001

From: Maarten Lankhorst maarten.lankhorst@linux.intel.com Date: Fri, 10 Nov 2017 12:34:53 +0100 Subject: [PATCH] drm/i915: Update watermark state correctly in sanitize_watermarks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

We no longer use intel_crtc->wm.active for watermarks any more, which was incorrect. But this uncovered a bug in sanitize_watermarks(), which meant that we wrote the correct watermarks, but the next update would still use the wrong hw watermarks for calculating. This caused all further updates to fail with -EINVAL and the log would reveal an error like the one below:

[ 10.043902] [drm:ilk_validate_wm_level.part.8 [i915]] Sprite WM0 too large 56 (max 0) [ 10.043960] [drm:ilk_validate_pipe_wm [i915]] LP0 watermark invalid [ 10.044030] [drm:intel_crtc_atomic_check [i915]] No valid intermediate pipe watermarks are possible

Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Fixes: b6b178a77210 ("drm/i915: Calculate ironlake intermediate watermarks correctly, v2.") Cc: stable@vger.kernel.org #v4.8+ Link: https://patchwork.freedesktop.org/patch/msgid/20171110113503.16253-1-maarten... Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 5c7540f3f5dc..63c8b9ccb31e 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -14443,6 +14443,8 @@ static void sanitize_watermarks(struct drm_device *dev)

cs->wm.need_postvbl_update = true; dev_priv->display.optimize_watermarks(intel_state, cs); + + to_intel_crtc_state(crtc->state)->wm = cs->wm; }

put_state: