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FAILED: patch "[PATCH] drm/i915/gen9: Only copy WM results for changed pipes to" failed to apply to 4.8-stable tree

PATCH [email protected] 1 participant 1 message Oct 28, 2016

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Stable branch DRM drivers Intel i915
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The patch below does not apply to the 4.8-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 <[email protected]>.

thanks,

greg k-h

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

Quoted 1 line

From 2722efb90b3420dee54b4cb3cdc7917efacc2dce Mon Sep 17 00:00:00 2001

From: Matt Roper <[email protected]>
Date: Wed, 17 Aug 2016 15:55:55 -0400
Subject: [PATCH] drm/i915/gen9: Only copy WM results for changed pipes to
skl_hw
MIME-Version: 1.0
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When we write watermark values to the hardware, those values are stored in dev_priv->wm.skl_hw. However with recent watermark changes, the results structure we're copying from only contains valid watermark and DDB values for the pipes that are actually changing; the values for other pipes remain 0. Thus a blind copy of the entire skl_wm_values structure will clobber the values for unchanged pipes...we need to be more selective and only copy over the values for the changing pipes.

This mistake was hidden until recently due to another bug that caused us to erroneously re-calculate watermarks for all active pipes rather than changing pipes. Only when that bug was fixed was the impact of this bug discovered (e.g., modesets failing with "Requested display configuration exceeds system watermark limitations" messages and leaving watermarks non-functional, even ones initiated by intel_fbdev_restore_mode).

Changes since v1:
- Add a function for copying a pipe's wm values (skl_copy_wm_for_pipe()) so we can reuse this later

Fixes 734fa01f3a17 ("drm/i915/gen9: Calculate watermarks during atomic 'check' (v2)")
Fixes 9b6130227495 ("drm/i915/gen9: Re-allocate DDB only for changed pipes")
Signed-off-by Matt Roper <[email protected]>
Signed-off-by Lyude <[email protected]>
Reviewed-by Matt Roper <[email protected]>
Cc [email protected]
Cc Maarten Lankhorst <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Radhakrishna Sripada <[email protected]>
Cc Hans de Goede <[email protected]>
Signed-off-by Maarten Lankhorst <[email protected]>
Link http://patchwork.freedesktop.org/patch/msgid/[email protected]
drivers/gpu/drm/i915/intel_pm.c +26 -2
index 5cd4840b78a3..177fdf3194f7 100644
@@ -4117,6 +4117,24 @@ skl_compute_ddb(struct drm_atomic_state *state)
 	return 0;
 }
 
+static void
+skl_copy_wm_for_pipe(struct skl_wm_values *dst,
+		     struct skl_wm_values *src,
+		     enum pipe pipe)
+{
+	dst->wm_linetime[pipe] = src->wm_linetime[pipe];
+	memcpy(dst->plane[pipe], src->plane[pipe],
+	       sizeof(dst->plane[pipe]));
+	memcpy(dst->plane_trans[pipe], src->plane_trans[pipe],
+	       sizeof(dst->plane_trans[pipe]));
+
+	dst->ddb.pipe[pipe] = src->ddb.pipe[pipe];
+	memcpy(dst->ddb.y_plane[pipe], src->ddb.y_plane[pipe],
+	       sizeof(dst->ddb.y_plane[pipe]));
+	memcpy(dst->ddb.plane[pipe], src->ddb.plane[pipe],
+	       sizeof(dst->ddb.plane[pipe]));
+}
+
 static int
 skl_compute_wm(struct drm_atomic_state *state)
 {

@@ -4189,8 +4207,10 @@ static void skl_update_wm(struct drm_crtc *crtc)
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct skl_wm_values *results = &dev_priv->wm.skl_results;
+	struct skl_wm_values *hw_vals = &dev_priv->wm.skl_hw;
 	struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state);
 	struct skl_pipe_wm *pipe_wm = &cstate->wm.skl.optimal;
+	int pipe;
 
 	if ((results->dirty_pipes & drm_crtc_mask(crtc)) == 0)
 		return;

@@ -4202,8 +4222,12 @@ static void skl_update_wm(struct drm_crtc *crtc)
 	skl_write_wm_values(dev_priv, results);
 	skl_flush_wm_values(dev_priv, results);
 
-	/* store the new configuration */
-	dev_priv->wm.skl_hw = *results;
+	/*
+	 * Store the new configuration (but only for the pipes that have
+	 * changed; the other values weren't recomputed).
+	 */
+	for_each_pipe_masked(dev_priv, pipe, results->dirty_pipes)
+		skl_copy_wm_for_pipe(hw_vals, results, pipe);
 
 	mutex_unlock(&dev_priv->wm.wm_mutex);
 }