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From: Daniel Vetter <daniel.vetter-/w4YWyX8dFk@public.gmane.org>
To: DRI Development
	<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>
Cc: Nouveau Dev
	<nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Intel Graphics Development
	<intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Radeon Dev
	<xorg-driver-ati-go0+a7rfsptAfugRpC6u6w@public.gmane.org>
Subject: [PATCH 37/37] drm: don't hold crtc mutexes for connector ->detect callbacks
Date: Wed, 12 Dec 2012 14:07:17 +0100	[thread overview]
Message-ID: <1355317637-16742-38-git-send-email-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <1355317637-16742-1-git-send-email-daniel.vetter-/w4YWyX8dFk@public.gmane.org>

The coup de grace of the entire journey. No more dropped frames every
10s on my testbox!

I've tried to audit all ->detect and ->get_modes callbacks, but things
became a bit fuzzy after trying to piece together the umpteenth
implemenation. Afaict most drivers just have bog-standard output
register frobbing with a notch of i2c edid reading, nothing which
could potentially race with the newly concurrent pageflip/set_cursor
code. The big exception is load-detection code which requires a
running pipe, but radeon/nouveau seem to to this without touching any
state which can be observed from page_flip (e.g. disabled crtcs
temporarily getting enabled and so a pageflip succeeding).

The only special case I could find is the i915 load detect code. That
uses the normal modeset interface to enable the load-detect crtc, and
so userspace could try to squeeze in a pageflip on the load-detect
pipe. So we need to grab the relevant crtc mutex in there, to avoid
the temporary crtc enabling to sneak out and be visible to userspace.

Note that the sysfs files already stopped grabbing the per-crtc locks,
since I didn't want to bother with doing a interruptible
modeset_lock_all. But since there's very little in-between breakage
(essentially just the ability for userspace to pageflip on load-detect
crtcs when it shouldn't on the i915 driver) I figured I don't need to
bother.

Signed-off-by: Daniel Vetter <daniel.vetter-/w4YWyX8dFk@public.gmane.org>
---
 drivers/gpu/drm/drm_crtc.c           |    5 +++--
 drivers/gpu/drm/drm_crtc_helper.c    |    8 ++++----
 drivers/gpu/drm/i915/intel_display.c |   10 ++++++++--
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 36c75e6..313d7d2 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1616,7 +1616,7 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:?]\n", out_resp->connector_id);
 
-	drm_modeset_lock_all(dev);
+	mutex_lock(&dev->mode_config.mutex);
 
 	obj = drm_mode_object_find(dev, out_resp->connector_id,
 				   DRM_MODE_OBJECT_CONNECTOR);
@@ -1713,7 +1713,8 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 	out_resp->count_encoders = encoders_count;
 
 out:
-	drm_modeset_unlock_all(dev);
+	mutex_unlock(&dev->mode_config.mutex);
+
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 400ef86..7b2d378 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -980,7 +980,7 @@ static void output_poll_execute(struct work_struct *work)
 	if (!drm_kms_helper_poll)
 		return;
 
-	drm_modeset_lock_all(dev);
+	mutex_lock(&dev->mode_config.mutex);
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 
 		/* Ignore forced connectors. */
@@ -1010,7 +1010,7 @@ static void output_poll_execute(struct work_struct *work)
 			changed = true;
 	}
 
-	drm_modeset_unlock_all(dev);
+	mutex_unlock(&dev->mode_config.mutex);
 
 	if (changed)
 		drm_kms_helper_hotplug_event(dev);
@@ -1070,7 +1070,7 @@ void drm_helper_hpd_irq_event(struct drm_device *dev)
 	if (!dev->mode_config.poll_enabled)
 		return;
 
-	drm_modeset_lock_all(dev);
+	mutex_lock(&dev->mode_config.mutex);
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 
 		/* Only handle HPD capable connectors. */
@@ -1088,7 +1088,7 @@ void drm_helper_hpd_irq_event(struct drm_device *dev)
 			changed = true;
 	}
 
-	drm_modeset_unlock_all(dev);
+	mutex_unlock(&dev->mode_config.mutex);
 
 	if (changed)
 		drm_kms_helper_hotplug_event(dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fd8cfeb..2429d39 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6390,6 +6390,8 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
 	if (encoder->crtc) {
 		crtc = encoder->crtc;
 
+		mutex_lock(&crtc->mutex);
+
 		old->dpms_mode = connector->dpms;
 		old->load_detect_temp = false;
 
@@ -6419,6 +6421,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
 		return false;
 	}
 
+	mutex_lock(&crtc->mutex);
 	intel_encoder->new_crtc = to_intel_crtc(crtc);
 	to_intel_connector(connector)->new_encoder = intel_encoder;
 
@@ -6446,6 +6449,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
 		DRM_DEBUG_KMS("reusing fbdev for load-detection framebuffer\n");
 	if (IS_ERR(fb)) {
 		DRM_DEBUG_KMS("failed to allocate framebuffer for load-detection\n");
+		mutex_unlock(&crtc->mutex);
 		return false;
 	}
 
@@ -6453,6 +6457,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
 		DRM_DEBUG_KMS("failed to set mode on load-detect pipe\n");
 		if (old->release_fb)
 			old->release_fb->funcs->destroy(old->release_fb);
+		mutex_unlock(&crtc->mutex);
 		return false;
 	}
 
@@ -6467,14 +6472,13 @@ void intel_release_load_detect_pipe(struct drm_connector *connector,
 	struct intel_encoder *intel_encoder =
 		intel_attached_encoder(connector);
 	struct drm_encoder *encoder = &intel_encoder->base;
+	struct drm_crtc *crtc = encoder->crtc;
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
 		      connector->base.id, drm_get_connector_name(connector),
 		      encoder->base.id, drm_get_encoder_name(encoder));
 
 	if (old->load_detect_temp) {
-		struct drm_crtc *crtc = encoder->crtc;
-
 		to_intel_connector(connector)->new_encoder = NULL;
 		intel_encoder->new_crtc = NULL;
 		intel_set_mode(crtc, NULL, 0, 0, NULL);
@@ -6490,6 +6494,8 @@ void intel_release_load_detect_pipe(struct drm_connector *connector,
 	/* Switch crtc and encoder back off if necessary */
 	if (old->dpms_mode != DRM_MODE_DPMS_ON)
 		connector->funcs->dpms(connector, old->dpms_mode);
+
+	mutex_unlock(&crtc->mutex);
 }
 
 /* Returns the clock of the currently programmed mode of the given pipe. */
-- 
1.7.10.4

  parent reply	other threads:[~2012-12-12 13:07 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-12 13:06 [PATCH 00/37] [RFC] revamped modeset locking Daniel Vetter
2012-12-12 13:06 ` [PATCH 01/37] drm: review locking rules in drm_crtc.c Daniel Vetter
2012-12-12 13:06 ` [PATCH 05/37] drm/i915: use drm_modeset_lock_all Daniel Vetter
2012-12-12 13:06 ` [PATCH 08/37] drm/shmobile: " Daniel Vetter
2012-12-12 13:06 ` [PATCH 10/37] drm: add per-crtc locks Daniel Vetter
2012-12-13 11:38   ` [Intel-gfx] " Ville Syrjälä
2012-12-13 11:54     ` Daniel Vetter
2012-12-13 14:25       ` Ville Syrjälä
2012-12-12 13:06 ` [PATCH 11/37] drm/radeon: add W|RREG32_IDX for MM_INDEX|DATA based mmio accesss Daniel Vetter
2012-12-12 13:07 ` [PATCH 25/37] drm: don't take modeset locks in getfb ioctl Daniel Vetter
2012-12-12 13:07 ` [PATCH 26/37] drm: fb refcounting for dirtyfb_ioctl Daniel Vetter
2012-12-12 13:07 ` [PATCH 31/37] drm/vmwgfx: add proper framebuffer refcounting Daniel Vetter
2012-12-12 13:07 ` [PATCH 33/37] drm/nouveau: try to protect nbo->pin_refcount Daniel Vetter
     [not found] ` <1355317637-16742-1-git-send-email-daniel.vetter-/w4YWyX8dFk@public.gmane.org>
2012-12-12 13:06   ` [PATCH 02/37] drm/doc: integrate drm_crtc.c kerneldoc Daniel Vetter
2012-12-12 13:06   ` [PATCH 03/37] drm: add drm_modeset_lock|unlock_all Daniel Vetter
2012-12-12 13:06   ` [PATCH 04/37] drm/i915: rework locking for intel_dpio|sbi_read|write Daniel Vetter
2012-12-12 20:54     ` [Intel-gfx] " Jesse Barnes
2012-12-12 22:00       ` Daniel Vetter
2012-12-12 22:05         ` Jesse Barnes
2012-12-12 13:06   ` [PATCH 06/37] drm/gma500: use drm_modeset_lock_all Daniel Vetter
2012-12-12 13:06   ` [PATCH 07/37] drm/ast: " Daniel Vetter
2012-12-12 13:06   ` [PATCH 09/37] drm/vmgfx: " Daniel Vetter
2012-12-12 13:06   ` [PATCH 12/37] drm/radeon: make indirect register access concurrency-safe Daniel Vetter
2012-12-12 13:06   ` [PATCH 13/37] drm/nouveau: protect evo_wait/evo_kick sections with a channel mutex Daniel Vetter
2012-12-12 13:06   ` [PATCH 14/37] drm: only take the crtc lock for ->cursor_set Daniel Vetter
2012-12-12 13:06   ` [PATCH 15/37] drm: only take the crtc lock for ->cursor_move Daniel Vetter
2012-12-13 11:03     ` [PATCH] " Daniel Vetter
2012-12-12 13:06   ` [PATCH 16/37] drm/<drivers>: reorder framebuffer init sequence Daniel Vetter
2012-12-13 11:05     ` [PATCH 1/2] " Daniel Vetter
     [not found]       ` <1355396719-25286-1-git-send-email-daniel.vetter-/w4YWyX8dFk@public.gmane.org>
2012-12-13 11:05         ` [PATCH 2/2] drm/exynos: " Daniel Vetter
2012-12-13 12:26           ` Inki Dae
2012-12-13 12:43             ` Daniel Vetter
2012-12-13 15:16               ` Inki Dae
2012-12-13 16:38                 ` Daniel Vetter
2012-12-14  4:57                   ` Inki Dae
2012-12-14  8:40                     ` Daniel Vetter
2012-12-12 13:06   ` [PATCH 17/37] drm: revamp locking around fb creation/destruction Daniel Vetter
2012-12-12 13:06   ` [PATCH 18/37] drm: create drm_framebuffer_lookup Daniel Vetter
2012-12-12 13:06   ` [PATCH 19/37] drm/gma500: move fbcon restore to lastclose Daniel Vetter
2012-12-12 13:07   ` [PATCH 20/37] drm: revamp framebuffer cleanup interfaces Daniel Vetter
2012-12-12 13:07   ` [PATCH 21/37] drm: reference framebuffers which are on the idr Daniel Vetter
2012-12-12 13:07   ` [PATCH 22/37] drm: nest modeset locks within fpriv->fbs_lock Daniel Vetter
2012-12-12 13:07   ` [PATCH 23/37] drm/i915: fixup overlay stolen memory leak Daniel Vetter
2012-12-12 13:07   ` [PATCH 24/37] drm: push modeset_lock_all into ->fb_create driver callbacks Daniel Vetter
2012-12-12 13:07   ` [PATCH 27/37] drm: refcounting for sprite framebuffers Daniel Vetter
2012-12-12 13:07   ` [PATCH 28/37] drm: encapsulate crtc->set_config calls Daniel Vetter
2012-12-12 13:07   ` [PATCH 29/37] drm: refcounting for crtc framebuffers Daniel Vetter
2012-12-12 13:07   ` [PATCH 30/37] drm/i915: dump refcount into framebuffer debugfs file Daniel Vetter
2012-12-12 13:07   ` [PATCH 32/37] drm: optimize drm_framebuffer_remove Daniel Vetter
2012-12-12 13:07   ` [PATCH 34/37] drm/ttm: fix fence locking in ttm_buffer_object_transfer Daniel Vetter
2012-12-12 14:48     ` Jerome Glisse
     [not found]       ` <CAH3drwbL34+omj2S3ArOPgoYRQ3uzPEiRPFLn7YkP3cOMnPiZg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-12-12 15:42         ` Daniel Vetter
2012-12-13 11:06     ` [PATCH] allow shmob+imx drm drivers to be compiled Daniel Vetter
2012-12-13 11:18     ` Daniel Vetter
2012-12-13 11:26     ` [PATCH] drm/ttm: fix fence locking in ttm_buffer_object_transfer Daniel Vetter
2012-12-12 13:07   ` [PATCH 35/37] drm/radeon: fix fence locking in the pageflip callback Daniel Vetter
2012-12-12 13:07   ` [PATCH 36/37] drm: only grab the crtc lock for pageflips Daniel Vetter
2012-12-12 13:07   ` Daniel Vetter [this message]
2012-12-12 14:18 ` [PATCH 00/37] [RFC] revamped modeset locking Daniel Vetter

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