[CI 1/2] drm/i915: Use fence_write() from rpm resume

[CI 1/2] drm/i915: Use fence_write() from rpm resume

[Chris Wilson]

During rpm resume we restore the fences, but we do not have the
protection of struct_mutex. This rules out updating the activity
tracking on the fences, and requires us to rely on the rpm as the
serialisation barrier instead.

[  350.298052] [drm:intel_runtime_resume [i915]] Resuming device
[  350.308606]
[  350.310520] ===============================
[  350.315560] [ INFO: suspicious RCU usage. ]
[  350.320554] 4.8.0-rc8-bsw-rapl+ #3133 Tainted: G     U  W
[  350.327208] -------------------------------
[  350.331977] ../drivers/gpu/drm/i915/i915_gem_request.h:371 suspicious rcu_dereference_protected() usage!
[  350.342619]
[  350.342619] other info that might help us debug this:
[  350.342619]
[  350.351593]
[  350.351593] rcu_scheduler_active = 1, debug_locks = 0
[  350.358952] 3 locks held by Xorg/320:
[  350.363077]  #0:  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa030589c>] drm_modeset_lock_all+0x3c/0xd0 [drm]
[  350.375162]  #1:  (crtc_ww_class_acquire){+.+.+.}, at: [<ffffffffa03058a6>] drm_modeset_lock_all+0x46/0xd0 [drm]
[  350.387022]  #2:  (crtc_ww_class_mutex){+.+.+.}, at: [<ffffffffa0305056>] drm_modeset_lock+0x36/0x110 [drm]
[  350.398236]
[  350.398236] stack backtrace:
[  350.403196] CPU: 1 PID: 320 Comm: Xorg Tainted: G     U  W       4.8.0-rc8-bsw-rapl+ #3133
[  350.412457] Hardware name: Intel Corporation CHERRYVIEW C0 PLATFORM/Braswell CRB, BIOS BRAS.X64.X088.R00.1510270350 10/27/2015
[  350.425212]  0000000000000000 ffff8801680a78c8 ffffffff81332187 ffff88016c5c5000
[  350.433611]  0000000000000001 ffff8801680a78f8 ffffffff810ca6da ffff88016cc8b0f0
[  350.442012]  ffff88016cc80000 ffff88016cc80000 ffff880177ad0000 ffff8801680a7948
[  350.450409] Call Trace:
[  350.453165]  [<ffffffff81332187>] dump_stack+0x67/0x90
[  350.458931]  [<ffffffff810ca6da>] lockdep_rcu_suspicious+0xea/0x120
[  350.466002]  [<ffffffffa039e8dd>] fence_update+0xbd/0x670 [i915]
[  350.472766]  [<ffffffffa039efe2>] i915_gem_restore_fences+0x52/0x70 [i915]
[  350.480496]  [<ffffffffa0368f42>] vlv_resume_prepare+0x72/0x570 [i915]
[  350.487839]  [<ffffffffa0369802>] intel_runtime_resume+0x102/0x210 [i915]
[  350.495442]  [<ffffffff8137f26f>] pci_pm_runtime_resume+0x7f/0xb0
[  350.502274]  [<ffffffff8137f1f0>] ? pci_restore_standard_config+0x40/0x40
[  350.509883]  [<ffffffff814401c5>] __rpm_callback+0x35/0x70
[  350.516037]  [<ffffffff8137f1f0>] ? pci_restore_standard_config+0x40/0x40
[  350.523646]  [<ffffffff81440224>] rpm_callback+0x24/0x80
[  350.529604]  [<ffffffff8137f1f0>] ? pci_restore_standard_config+0x40/0x40
[  350.537212]  [<ffffffff814417bd>] rpm_resume+0x4ad/0x740
[  350.543161]  [<ffffffff81441aa1>] __pm_runtime_resume+0x51/0x80
[  350.549824]  [<ffffffffa03889c8>] intel_runtime_pm_get+0x28/0x90 [i915]
[  350.557265]  [<ffffffffa0388a53>] intel_display_power_get+0x23/0x50 [i915]
[  350.565001]  [<ffffffffa03ef23d>] intel_atomic_commit_tail+0xdfd/0x10b0 [i915]
[  350.573106]  [<ffffffffa034b2e9>] ? drm_atomic_helper_swap_state+0x159/0x300 [drm_kms_helper]
[  350.582659]  [<ffffffff81615091>] ? _raw_spin_unlock+0x31/0x50
[  350.589205]  [<ffffffffa034b2e9>] ? drm_atomic_helper_swap_state+0x159/0x300 [drm_kms_helper]
[  350.598787]  [<ffffffffa03ef8a5>] intel_atomic_commit+0x3b5/0x500 [i915]
[  350.606319]  [<ffffffffa03061dc>] ? drm_atomic_set_crtc_for_connector+0xcc/0x100 [drm]
[  350.615209]  [<ffffffffa0306b49>] drm_atomic_commit+0x49/0x50 [drm]
[  350.622242]  [<ffffffffa034dee8>] drm_atomic_helper_set_config+0x88/0xc0 [drm_kms_helper]
[  350.631419]  [<ffffffffa02f94ac>] drm_mode_set_config_internal+0x6c/0x120 [drm]
[  350.639623]  [<ffffffffa02fa94c>] drm_mode_setcrtc+0x22c/0x4d0 [drm]
[  350.646760]  [<ffffffffa02f0f19>] drm_ioctl+0x209/0x460 [drm]
[  350.653217]  [<ffffffffa02fa720>] ? drm_mode_getcrtc+0x150/0x150 [drm]
[  350.660536]  [<ffffffff810c984a>] ? __lock_is_held+0x4a/0x70
[  350.666885]  [<ffffffff81202303>] do_vfs_ioctl+0x93/0x6b0
[  350.672939]  [<ffffffff8120f843>] ? __fget+0x113/0x200
[  350.678797]  [<ffffffff8120f735>] ? __fget+0x5/0x200
[  350.684361]  [<ffffffff81202964>] SyS_ioctl+0x44/0x80
[  350.690030]  [<ffffffff81001deb>] do_syscall_64+0x5b/0x120
[  350.696184]  [<ffffffff81615ada>] entry_SYSCALL64_slow_path+0x25/0x25

Note we also have to remember the lesson from commit 4fc788f5ee3d
("drm/i915: Flush delayed fence releases after reset") where we have to
flush any changes to the fence on restore.

v2: Replace call to release user mmaps with an assertion that they have
already been zapped.

Fixes: 49ef5294cda2 ("drm/i915: Move fence tracking from object to vma")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_fence.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_fence.c b/drivers/gpu/drm/i915/i915_gem_fence.c
index 8df1fa7234e8..2c7ba0ee127c 100644
--- a/drivers/gpu/drm/i915/i915_gem_fence.c
+++ b/drivers/gpu/drm/i915/i915_gem_fence.c
@@ -290,6 +290,8 @@ i915_vma_put_fence(struct i915_vma *vma)
 {
 	struct drm_i915_fence_reg *fence = vma->fence;
 
+	assert_rpm_wakelock_held(to_i915(vma->vm->dev));
+
 	if (!fence)
 		return 0;
 
@@ -341,6 +343,8 @@ i915_vma_get_fence(struct i915_vma *vma)
 	struct drm_i915_fence_reg *fence;
 	struct i915_vma *set = i915_gem_object_is_tiled(vma->obj) ? vma : NULL;
 
+	assert_rpm_wakelock_held(to_i915(vma->vm->dev));
+
 	/* Just update our place in the LRU if our fence is getting reused. */
 	if (vma->fence) {
 		fence = vma->fence;
@@ -371,6 +375,12 @@ void i915_gem_restore_fences(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	int i;
 
+	/* Note that this may be called outside of struct_mutex, by
+	 * runtime suspend/resume. The barrier we require is enforced by
+	 * rpm itself - all access to fences/GTT are only within an rpm
+	 * wakeref, and to acquire that wakeref you must pass through here.
+	 */
+
 	for (i = 0; i < dev_priv->num_fence_regs; i++) {
 		struct drm_i915_fence_reg *reg = &dev_priv->fence_regs[i];
 		struct i915_vma *vma = reg->vma;
@@ -379,10 +389,17 @@ void i915_gem_restore_fences(struct drm_device *dev)
 		 * Commit delayed tiling changes if we have an object still
 		 * attached to the fence, otherwise just clear the fence.
 		 */
-		if (vma && !i915_gem_object_is_tiled(vma->obj))
+		if (vma && !i915_gem_object_is_tiled(vma->obj)) {
+			GEM_BUG_ON(!reg->dirty);
+			GEM_BUG_ON(vma->obj->fault_mappable);
+
+			list_move(&reg->link, &dev_priv->mm.fence_list);
+			vma->fence = NULL;
 			vma = NULL;
+		}
 
-		fence_update(reg, vma);
+		fence_write(reg, vma);
+		reg->vma = vma;
 	}
 }
 
-- 
2.9.3

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[CI 2/2] drm/i915: Update debugfs describe_obj() to show fault-mappable

[Chris Wilson]

The current meaning of whether an object has a GGTT vma is very
ill-defined (and note we don't check for any partials either), it just
means that at some point it was in the GGTT but it may not be now. The
information we really care about here is whether it is taking up
precious mappable aperture space. This is the obj->fault_mappable flag.
We have a redundant long form reprinting of this information, so remove
that in favour of the compact flag.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 358663e833d6..2e312e0f2670 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -107,7 +107,7 @@ static char get_tiling_flag(struct drm_i915_gem_object *obj)
 
 static char get_global_flag(struct drm_i915_gem_object *obj)
 {
-	return i915_gem_object_to_ggtt(obj, NULL) ?  'g' : ' ';
+	return obj->fault_mappable ? 'g' : ' ';
 }
 
 static char get_pin_mapped_flag(struct drm_i915_gem_object *obj)
@@ -186,15 +186,6 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 	}
 	if (obj->stolen)
 		seq_printf(m, " (stolen: %08llx)", obj->stolen->start);
-	if (obj->pin_display || obj->fault_mappable) {
-		char s[3], *t = s;
-		if (obj->pin_display)
-			*t++ = 'p';
-		if (obj->fault_mappable)
-			*t++ = 'f';
-		*t = '\0';
-		seq_printf(m, " (%s mappable)", s);
-	}
 
 	engine = i915_gem_active_get_engine(&obj->last_write,
 					    &dev_priv->drm.struct_mutex);
-- 
2.9.3

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✗ Fi.CI.BAT: failure for series starting with [CI,1/2] drm/i915: Use fence_write() from rpm resume

[Patchwork]

== Series Details ==

Series: series starting with [CI,1/2] drm/i915: Use fence_write() from rpm resume
URL   : https://patchwork.freedesktop.org/series/13642/
State : failure

== Summary ==

Series 13642v1 Series without cover letter
https://patchwork.freedesktop.org/api/1.0/series/13642/revisions/1/mbox/

Test kms_pipe_crc_basic:
        Subgroup bad-nb-words-1:
                pass       -> DMESG-WARN (fi-ilk-650)
        Subgroup suspend-read-crc-pipe-b:
                dmesg-warn -> PASS       (fi-byt-j1900)
Test vgem_reload_basic:
                pass       -> FAIL       (fi-hsw-4770)

fi-bdw-5557u     total:248  pass:232  dwarn:0   dfail:0   fail:0   skip:16 
fi-bsw-n3050     total:248  pass:205  dwarn:0   dfail:0   fail:0   skip:43 
fi-bxt-t5700     total:248  pass:217  dwarn:0   dfail:0   fail:0   skip:31 
fi-byt-j1900     total:248  pass:214  dwarn:1   dfail:0   fail:1   skip:32 
fi-byt-n2820     total:248  pass:211  dwarn:0   dfail:0   fail:1   skip:36 
fi-hsw-4770      total:248  pass:223  dwarn:0   dfail:0   fail:1   skip:24 
fi-hsw-4770r     total:248  pass:225  dwarn:0   dfail:0   fail:0   skip:23 
fi-ilk-650       total:248  pass:184  dwarn:1   dfail:0   fail:2   skip:61 
fi-ivb-3520m     total:248  pass:222  dwarn:0   dfail:0   fail:0   skip:26 
fi-ivb-3770      total:248  pass:222  dwarn:0   dfail:0   fail:0   skip:26 
fi-kbl-7200u     total:248  pass:223  dwarn:0   dfail:0   fail:0   skip:25 
fi-skl-6260u     total:248  pass:233  dwarn:0   dfail:0   fail:0   skip:15 
fi-skl-6700hq    total:248  pass:225  dwarn:0   dfail:0   fail:0   skip:23 
fi-skl-6700k     total:248  pass:222  dwarn:1   dfail:0   fail:0   skip:25 
fi-skl-6770hq    total:248  pass:231  dwarn:1   dfail:0   fail:1   skip:15 
fi-snb-2520m     total:248  pass:211  dwarn:0   dfail:0   fail:0   skip:37 
fi-snb-2600      total:248  pass:210  dwarn:0   dfail:0   fail:0   skip:38 

Results at /archive/results/CI_IGT_test/Patchwork_2686/

46271d41e30090d7fc996e8f5abde6a59f51038b drm-intel-nightly: 2016y-10m-12d-11h-06m-41s UTC integration manifest
3556a2e drm/i915: Update debugfs describe_obj() to show fault-mappable
652a473 drm/i915: Use fence_write() from rpm resume

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