[Intel-gfx] [PATCH] drm/i915: Don't check modeset state in the hw state force restore path

[Ander Conselvan de Oliveira]

Since the force restore logic will restore the CRTCs state one at a
time, it is possible that the state will be inconsistent until the whole
operation finishes. A call to intel_modeset_check_state() is done once
it's over, so don't check the state multiple times in between. This
regression was introduced in:

commit 7f27126ea3db6ade886f18fd39caf0ff0cd1d37f
Author: Jesse Barnes <jbarnes at virtuousgeek.org>
Date:   Wed Nov 5 14:26:06 2014 -0800

    drm/i915: factor out compute_config from __intel_set_mode v3

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94431
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
---

Hi,

This patch applies on top of nightly, but it is only relevant without
Maarten's "drm/i915: Convert to atomic, part 2" series, because of the
changes to the hw state read out and force restore logic.

The regression exists since 3.19.

---
 drivers/gpu/drm/i915/intel_display.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 16e159d..24fb7ce 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -87,7 +87,8 @@ static void ironlake_pch_clock_get(struct intel_crtc *crtc,
 				   struct intel_crtc_state *pipe_config);
 
 static int intel_set_mode(struct drm_crtc *crtc,
-			  struct drm_atomic_state *state);
+			  struct drm_atomic_state *state,
+			  bool check);
 static int intel_framebuffer_init(struct drm_device *dev,
 				  struct intel_framebuffer *ifb,
 				  struct drm_mode_fb_cmd2 *mode_cmd,
@@ -10282,7 +10283,7 @@ retry:
 
 	drm_mode_copy(&crtc_state->base.mode, mode);
 
-	if (intel_set_mode(crtc, state)) {
+	if (intel_set_mode(crtc, state, true)) {
 		DRM_DEBUG_KMS("failed to set mode on load-detect pipe\n");
 		if (old->release_fb)
 			old->release_fb->funcs->destroy(old->release_fb);
@@ -10356,7 +10357,7 @@ void intel_release_load_detect_pipe(struct drm_connector *connector,
 		if (ret)
 			goto fail;
 
-		ret = intel_set_mode(crtc, state);
+		ret = intel_set_mode(crtc, state, true);
 		if (ret)
 			goto fail;
 
@@ -12832,20 +12833,22 @@ static int __intel_set_mode(struct drm_crtc *modeset_crtc,
 }
 
 static int intel_set_mode_with_config(struct drm_crtc *crtc,
-				      struct intel_crtc_state *pipe_config)
+				      struct intel_crtc_state *pipe_config,
+				      bool check)
 {
 	int ret;
 
 	ret = __intel_set_mode(crtc, pipe_config);
 
-	if (ret == 0)
+	if (ret == 0 && check)
 		intel_modeset_check_state(crtc->dev);
 
 	return ret;
 }
 
 static int intel_set_mode(struct drm_crtc *crtc,
-			  struct drm_atomic_state *state)
+			  struct drm_atomic_state *state,
+			  bool check)
 {
 	struct intel_crtc_state *pipe_config;
 	int ret = 0;
@@ -12856,7 +12859,7 @@ static int intel_set_mode(struct drm_crtc *crtc,
 		goto out;
 	}
 
-	ret = intel_set_mode_with_config(crtc, pipe_config);
+	ret = intel_set_mode_with_config(crtc, pipe_config, check);
 	if (ret)
 		goto out;
 
@@ -12933,7 +12936,7 @@ void intel_crtc_restore_mode(struct drm_crtc *crtc)
 	intel_modeset_setup_plane_state(state, crtc, &crtc->mode,
 					crtc->primary->fb, crtc->x, crtc->y);
 
-	ret = intel_set_mode(crtc, state);
+	ret = intel_set_mode(crtc, state, false);
 	if (ret)
 		drm_atomic_state_free(state);
 }
@@ -13133,7 +13136,7 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
 
 	primary_plane_was_visible = primary_plane_visible(set->crtc);
 
-	ret = intel_set_mode_with_config(set->crtc, pipe_config);
+	ret = intel_set_mode_with_config(set->crtc, pipe_config, true);
 
 	if (ret == 0 &&
 	    pipe_config->base.enable &&
-- 
2.1.0