arch-linux-kernel/0002-Revert-drm-i915-edp-Allow-alternate-fixed-mode-for-e.patch

From bc49947e26285cf644492f9d58981e3c985d8c76 Mon Sep 17 00:00:00 2001
Message-Id: <bc49947e26285cf644492f9d58981e3c985d8c76.1531335939.git.jan.steffens@gmail.com>
In-Reply-To: <a2d2476ffec7d988b1a5396586869570e0d6f9d8.1531335939.git.jan.steffens@gmail.com>
References: <a2d2476ffec7d988b1a5396586869570e0d6f9d8.1531335939.git.jan.steffens@gmail.com>
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 16 May 2018 11:01:10 +0300
Subject: [PATCH 2/4] Revert "drm/i915/edp: Allow alternate fixed mode for eDP
 if available."

This reverts commit dc911f5bd8aacfcf8aabd5c26c88e04c837a938e.

Per the report, no matter what display mode you select with xrandr, the
i915 driver will always select the alternate fixed mode. For the
reporter this means that the display will always run at 40Hz which is
quite annoying. This may be due to the mode comparison.

But there are some other potential issues. The choice of alt_fixed_mode
seems dubious. It's the first non-preferred mode, but there are no
guarantees that the only difference would be refresh rate. Similarly,
there may be more than one preferred mode in the probed modes list, and
the commit changes the preferred mode selection to choose the last one
on the list instead of the first.

(Note that the probed modes list is the raw, unfiltered, unsorted list
of modes from drm_add_edid_modes(), not the pretty result after a
drm_helper_probe_single_connector_modes() call.)

Finally, we already have eerily similar code in place to find the
downclock mode for DRRS that seems like could be reused here.

Back to the drawing board.

Note: This is a hand-crafted revert due to conflicts. If it fails to
backport, please just try reverting the original commit directly.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105469
Reported-by: Rune Petersen <rune@megahurts.dk>
Reported-by: Mark Spencer <n7u4722r35@ynzlx.anonbox.net>
Fixes: dc911f5bd8aa ("drm/i915/edp: Allow alternate fixed mode for eDP if available.")
Cc: Clint Taylor <clinton.a.taylor@intel.com>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180516080110.22770-1-jani.nikula@intel.com
---
 drivers/gpu/drm/i915/intel_dp.c    | 38 ++++--------------------------
 drivers/gpu/drm/i915/intel_drv.h   |  2 --
 drivers/gpu/drm/i915/intel_dsi.c   |  2 +-
 drivers/gpu/drm/i915/intel_dvo.c   |  2 +-
 drivers/gpu/drm/i915/intel_lvds.c  |  3 +--
 drivers/gpu/drm/i915/intel_panel.c |  6 -----
 6 files changed, 8 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index cd6e87756509..492b0cb9bb2b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1674,23 +1674,6 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	return bpp;
 }
 
-static bool intel_edp_compare_alt_mode(struct drm_display_mode *m1,
-				       struct drm_display_mode *m2)
-{
-	bool bres = false;
-
-	if (m1 && m2)
-		bres = (m1->hdisplay == m2->hdisplay &&
-			m1->hsync_start == m2->hsync_start &&
-			m1->hsync_end == m2->hsync_end &&
-			m1->htotal == m2->htotal &&
-			m1->vdisplay == m2->vdisplay &&
-			m1->vsync_start == m2->vsync_start &&
-			m1->vsync_end == m2->vsync_end &&
-			m1->vtotal == m2->vtotal);
-	return bres;
-}
-
 bool
 intel_dp_compute_config(struct intel_encoder *encoder,
 			struct intel_crtc_state *pipe_config,
@@ -1737,16 +1720,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 		pipe_config->has_audio = intel_conn_state->force_audio == HDMI_AUDIO_ON;
 
 	if (intel_dp_is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
-		struct drm_display_mode *panel_mode =
-			intel_connector->panel.alt_fixed_mode;
-		struct drm_display_mode *req_mode = &pipe_config->base.mode;
-
-		if (!intel_edp_compare_alt_mode(req_mode, panel_mode))
-			panel_mode = intel_connector->panel.fixed_mode;
-
-		drm_mode_debug_printmodeline(panel_mode);
-
-		intel_fixed_panel_mode(panel_mode, adjusted_mode);
+		intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
+				       adjusted_mode);
 
 		if (INTEL_GEN(dev_priv) >= 9) {
 			int ret;
@@ -6123,7 +6098,6 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct drm_connector *connector = &intel_connector->base;
 	struct drm_display_mode *fixed_mode = NULL;
-	struct drm_display_mode *alt_fixed_mode = NULL;
 	struct drm_display_mode *downclock_mode = NULL;
 	bool has_dpcd;
 	struct drm_display_mode *scan;
@@ -6178,14 +6152,13 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	}
 	intel_connector->edid = edid;
 
-	/* prefer fixed mode from EDID if available, save an alt mode also */
+	/* prefer fixed mode from EDID if available */
 	list_for_each_entry(scan, &connector->probed_modes, head) {
 		if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
 			fixed_mode = drm_mode_duplicate(dev, scan);
 			downclock_mode = intel_dp_drrs_init(
 						intel_connector, fixed_mode);
-		} else if (!alt_fixed_mode) {
-			alt_fixed_mode = drm_mode_duplicate(dev, scan);
+			break;
 		}
 	}
 
@@ -6222,8 +6195,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 			      pipe_name(pipe));
 	}
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, alt_fixed_mode,
-			 downclock_mode);
+	intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
 	intel_connector->panel.backlight.power = intel_edp_backlight_power;
 	intel_panel_setup_backlight(connector, pipe);
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a80fbad9be0f..7f3e83f17adb 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -269,7 +269,6 @@ struct intel_encoder {
 
 struct intel_panel {
 	struct drm_display_mode *fixed_mode;
-	struct drm_display_mode *alt_fixed_mode;
 	struct drm_display_mode *downclock_mode;
 
 	/* backlight */
@@ -1820,7 +1819,6 @@ void intel_overlay_reset(struct drm_i915_private *dev_priv);
 /* intel_panel.c */
 int intel_panel_init(struct intel_panel *panel,
 		     struct drm_display_mode *fixed_mode,
-		     struct drm_display_mode *alt_fixed_mode,
 		     struct drm_display_mode *downclock_mode);
 void intel_panel_fini(struct intel_panel *panel);
 void intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 384b37e2da70..f349b3920199 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -1852,7 +1852,7 @@ void intel_dsi_init(struct drm_i915_private *dev_priv)
 	connector->display_info.width_mm = fixed_mode->width_mm;
 	connector->display_info.height_mm = fixed_mode->height_mm;
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, NULL, NULL);
+	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
 	intel_panel_setup_backlight(connector, INVALID_PIPE);
 
 	intel_dsi_add_properties(intel_connector);
diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
index 6604806f89d5..61d908e0df0e 100644
--- a/drivers/gpu/drm/i915/intel_dvo.c
+++ b/drivers/gpu/drm/i915/intel_dvo.c
@@ -542,7 +542,7 @@ void intel_dvo_init(struct drm_i915_private *dev_priv)
 			 */
 			intel_panel_init(&intel_connector->panel,
 					 intel_dvo_get_current_mode(intel_encoder),
-					 NULL, NULL);
+					 NULL);
 			intel_dvo->panel_wants_dither = true;
 		}
 
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 34dd1e5233ac..48f618dc9abb 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1180,8 +1180,7 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
 out:
 	mutex_unlock(&dev->mode_config.mutex);
 
-	intel_panel_init(&intel_connector->panel, fixed_mode, NULL,
-			 downclock_mode);
+	intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
 	intel_panel_setup_backlight(connector, INVALID_PIPE);
 
 	lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 41d00b1603e3..b443278e569c 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1928,30 +1928,24 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
 
 int intel_panel_init(struct intel_panel *panel,
 		     struct drm_display_mode *fixed_mode,
-		     struct drm_display_mode *alt_fixed_mode,
 		     struct drm_display_mode *downclock_mode)
 {
 	intel_panel_init_backlight_funcs(panel);
 
 	panel->fixed_mode = fixed_mode;
-	panel->alt_fixed_mode = alt_fixed_mode;
 	panel->downclock_mode = downclock_mode;
 
 	return 0;
 }
 
 void intel_panel_fini(struct intel_panel *panel)
 {
 	struct intel_connector *intel_connector =
 		container_of(panel, struct intel_connector, panel);
 
 	if (panel->fixed_mode)
 		drm_mode_destroy(intel_connector->base.dev, panel->fixed_mode);
 
-	if (panel->alt_fixed_mode)
-		drm_mode_destroy(intel_connector->base.dev,
-				panel->alt_fixed_mode);
-
 	if (panel->downclock_mode)
 		drm_mode_destroy(intel_connector->base.dev,
 				panel->downclock_mode);
-- 
2.18.0