[PATCH] drm/i915: Discard previous atomic state on resume if connectors change

[PATCH] drm/i915: Discard previous atomic state on resume if connectors change

[Lyude]

If an MST device is disconnected while the machine is suspended, the
number of connectors will change as well after we call
intel_dp_mst_resume(). This means that any previous atomic state we had
before suspending is no longer valid, since it'll still be pointing to
missing connectors. We need to check for this before committing the
state, otherwise we'll kernel panic on resume whenever if any MST
display was disconnected before we started resuming:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffffa01588ef>] drm_atomic_helper_check_modeset+0x29f/0xb40 [drm_kms_helper]
Call Trace:
 [<ffffffffa02354f4>] intel_atomic_check+0x34/0x1180 [i915]
 [<ffffffff810e6c3f>] ? mark_held_locks+0x6f/0xa0
 [<ffffffff810e6d99>] ? trace_hardirqs_on_caller+0x129/0x1b0
 [<ffffffffa00ff1d2>] drm_atomic_check_only+0x192/0x620 [drm]
 [<ffffffff813ee001>] ? pci_pm_thaw+0x21/0x90
 [<ffffffffa00ff677>] drm_atomic_commit+0x17/0x60 [drm]
 [<ffffffffa023e0ad>] intel_display_resume+0xbd/0x160 [i915]
 [<ffffffff813ee070>] ? pci_pm_thaw+0x90/0x90
 [<ffffffffa01b60d8>] i915_drm_resume+0xd8/0x160 [i915]
 [<ffffffffa01b6185>] i915_pm_resume+0x25/0x30 [i915]
 [<ffffffff813ee0d4>] pci_pm_resume+0x64/0xa0
 [<ffffffff814d9ea0>] dpm_run_callback+0x90/0x190
 [<ffffffff814da455>] device_resume+0xd5/0x1f0
 [<ffffffff814da58d>] async_resume+0x1d/0x50
 [<ffffffff810b6718>] async_run_entry_fn+0x48/0x150
 [<ffffffff810acc19>] process_one_work+0x1e9/0x5c0
 [<ffffffff810acb96>] ? process_one_work+0x166/0x5c0
 [<ffffffff810ad038>] worker_thread+0x48/0x4e0
 [<ffffffff810acff0>] ? process_one_work+0x5c0/0x5c0
 [<ffffffff810b3794>] kthread+0xe4/0x100
 [<ffffffff81742672>] ret_from_fork+0x22/0x50
 [<ffffffff810b36b0>] ? kthread_create_on_node+0x200/0x200

Cc: stable@vger.kernel.org
Signed-off-by: Lyude <cpaul@redhat.com>
---
 drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6e0d828..252c06c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15945,6 +15945,17 @@ void intel_display_resume(struct drm_device *dev)
 	dev_priv->modeset_restore_state = NULL;
 
 	/*
+	 * With MST, the number of connectors can change between suspend and
+	 * resume, which means that the state we want to restore might now be
+	 * impossible to use since it'll be pointing to non-existant
+	 * connectors.
+	 */
+	if (state->num_connector != dev->mode_config.num_connector) {
+		drm_atomic_state_free(state);
+		state = NULL;
+	}
+
+	/*
 	 * This is a cludge because with real atomic modeset mode_config.mutex
 	 * won't be taken. Unfortunately some probed state like
 	 * audio_codec_enable is still protected by mode_config.mutex, so lock
-- 
2.5.5

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Re: [Intel-gfx] [PATCH] drm/i915: Discard previous atomic state on resume if connectors change

[Daniel Vetter]

On Tue, May 03, 2016 at 10:03:40AM -0400, Lyude wrote:
> If an MST device is disconnected while the machine is suspended, the
> number of connectors will change as well after we call
> intel_dp_mst_resume(). This means that any previous atomic state we had
> before suspending is no longer valid, since it'll still be pointing to
> missing connectors. We need to check for this before committing the
> state, otherwise we'll kernel panic on resume whenever if any MST
> display was disconnected before we started resuming:
> 
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> IP: [<ffffffffa01588ef>] drm_atomic_helper_check_modeset+0x29f/0xb40 [drm_kms_helper]
> Call Trace:
>  [<ffffffffa02354f4>] intel_atomic_check+0x34/0x1180 [i915]
>  [<ffffffff810e6c3f>] ? mark_held_locks+0x6f/0xa0
>  [<ffffffff810e6d99>] ? trace_hardirqs_on_caller+0x129/0x1b0
>  [<ffffffffa00ff1d2>] drm_atomic_check_only+0x192/0x620 [drm]
>  [<ffffffff813ee001>] ? pci_pm_thaw+0x21/0x90
>  [<ffffffffa00ff677>] drm_atomic_commit+0x17/0x60 [drm]
>  [<ffffffffa023e0ad>] intel_display_resume+0xbd/0x160 [i915]
>  [<ffffffff813ee070>] ? pci_pm_thaw+0x90/0x90
>  [<ffffffffa01b60d8>] i915_drm_resume+0xd8/0x160 [i915]
>  [<ffffffffa01b6185>] i915_pm_resume+0x25/0x30 [i915]
>  [<ffffffff813ee0d4>] pci_pm_resume+0x64/0xa0
>  [<ffffffff814d9ea0>] dpm_run_callback+0x90/0x190
>  [<ffffffff814da455>] device_resume+0xd5/0x1f0
>  [<ffffffff814da58d>] async_resume+0x1d/0x50
>  [<ffffffff810b6718>] async_run_entry_fn+0x48/0x150
>  [<ffffffff810acc19>] process_one_work+0x1e9/0x5c0
>  [<ffffffff810acb96>] ? process_one_work+0x166/0x5c0
>  [<ffffffff810ad038>] worker_thread+0x48/0x4e0
>  [<ffffffff810acff0>] ? process_one_work+0x5c0/0x5c0
>  [<ffffffff810b3794>] kthread+0xe4/0x100
>  [<ffffffff81742672>] ret_from_fork+0x22/0x50
>  [<ffffffff810b36b0>] ? kthread_create_on_node+0x200/0x200
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Lyude <cpaul@redhat.com>

This should be addressed by the connector refcounting fixes Dave Airlie
has for 4.7 (not all merged yet though). Can you please retest with those?
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 6e0d828..252c06c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15945,6 +15945,17 @@ void intel_display_resume(struct drm_device *dev)
>  	dev_priv->modeset_restore_state = NULL;
>  
>  	/*
> +	 * With MST, the number of connectors can change between suspend and
> +	 * resume, which means that the state we want to restore might now be
> +	 * impossible to use since it'll be pointing to non-existant
> +	 * connectors.
> +	 */
> +	if (state->num_connector != dev->mode_config.num_connector) {
> +		drm_atomic_state_free(state);
> +		state = NULL;
> +	}
> +
> +	/*
>  	 * This is a cludge because with real atomic modeset mode_config.mutex
>  	 * won't be taken. Unfortunately some probed state like
>  	 * audio_codec_enable is still protected by mode_config.mutex, so lock
> -- 
> 2.5.5
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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✗ Fi.CI.BAT: failure for drm/i915: Discard previous atomic state on resume if connectors change

[Patchwork]

== Series Details ==

Series: drm/i915: Discard previous atomic state on resume if connectors change
URL   : https://patchwork.freedesktop.org/series/6673/
State : failure

== Summary ==

Series 6673v1 drm/i915: Discard previous atomic state on resume if connectors change
http://patchwork.freedesktop.org/api/1.0/series/6673/revisions/1/mbox/

Test gem_exec_flush:
        Subgroup basic-uc-pro-default:
                fail       -> PASS       (bsw-nuc-2)
        Subgroup basic-uc-pro-default-interruptible:
                fail       -> PASS       (byt-nuc)
Test kms_flip:
        Subgroup basic-flip-vs-wf_vblank:
                pass       -> FAIL       (snb-x220t)
        Subgroup basic-plain-flip:
                incomplete -> PASS       (hsw-brixbox)
Test kms_pipe_crc_basic:
        Subgroup hang-read-crc-pipe-a:
                pass       -> DMESG-WARN (snb-dellxps)

bdw-nuci7-2      total:221  pass:209  dwarn:0   dfail:0   fail:0   skip:12 
bdw-ultra        total:221  pass:196  dwarn:0   dfail:0   fail:0   skip:25 
bsw-nuc-2        total:220  pass:177  dwarn:0   dfail:0   fail:2   skip:41 
byt-nuc          total:220  pass:176  dwarn:0   dfail:0   fail:3   skip:41 
hsw-brixbox      total:221  pass:195  dwarn:0   dfail:0   fail:0   skip:26 
hsw-gt2          total:221  pass:199  dwarn:0   dfail:0   fail:1   skip:21 
ilk-hp8440p      total:221  pass:158  dwarn:0   dfail:0   fail:2   skip:61 
ivb-t430s        total:221  pass:190  dwarn:0   dfail:0   fail:0   skip:31 
skl-i7k-2        total:221  pass:194  dwarn:0   dfail:0   fail:0   skip:27 
skl-nuci5        total:221  pass:210  dwarn:0   dfail:0   fail:0   skip:11 
snb-dellxps      total:221  pass:178  dwarn:1   dfail:0   fail:0   skip:42 
snb-x220t        total:221  pass:178  dwarn:0   dfail:0   fail:2   skip:41 

Results at /archive/results/CI_IGT_test/Patchwork_2130/

e10fc3de61f519461c4a05c9ef28c67b14f297b0 drm-intel-nightly: 2016y-05m-03d-13h-50m-23s UTC integration manifest
0d999ac drm/i915: Discard previous atomic state on resume if connectors change

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Re: [Intel-gfx] [PATCH] drm/i915: Discard previous atomic state on resume if connectors change

[Lyude Paul]

Yeah airlied said the same thing. This patch is more intended for just 4.6 since
the refcounting patch isn't very likely to get into 4.6.

On Tue, 2016-05-03 at 16:29 +0200, Daniel Vetter wrote:
> On Tue, May 03, 2016 at 10:03:40AM -0400, Lyude wrote:
> > 
> > If an MST device is disconnected while the machine is suspended, the
> > number of connectors will change as well after we call
> > intel_dp_mst_resume(). This means that any previous atomic state we had
> > before suspending is no longer valid, since it'll still be pointing to
> > missing connectors. We need to check for this before committing the
> > state, otherwise we'll kernel panic on resume whenever if any MST
> > display was disconnected before we started resuming:
> > 
> > BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> > IP: [<ffffffffa01588ef>] drm_atomic_helper_check_modeset+0x29f/0xb40
> > [drm_kms_helper]
> > Call Trace:
> >  [<ffffffffa02354f4>] intel_atomic_check+0x34/0x1180 [i915]
> >  [<ffffffff810e6c3f>] ? mark_held_locks+0x6f/0xa0
> >  [<ffffffff810e6d99>] ? trace_hardirqs_on_caller+0x129/0x1b0
> >  [<ffffffffa00ff1d2>] drm_atomic_check_only+0x192/0x620 [drm]
> >  [<ffffffff813ee001>] ? pci_pm_thaw+0x21/0x90
> >  [<ffffffffa00ff677>] drm_atomic_commit+0x17/0x60 [drm]
> >  [<ffffffffa023e0ad>] intel_display_resume+0xbd/0x160 [i915]
> >  [<ffffffff813ee070>] ? pci_pm_thaw+0x90/0x90
> >  [<ffffffffa01b60d8>] i915_drm_resume+0xd8/0x160 [i915]
> >  [<ffffffffa01b6185>] i915_pm_resume+0x25/0x30 [i915]
> >  [<ffffffff813ee0d4>] pci_pm_resume+0x64/0xa0
> >  [<ffffffff814d9ea0>] dpm_run_callback+0x90/0x190
> >  [<ffffffff814da455>] device_resume+0xd5/0x1f0
> >  [<ffffffff814da58d>] async_resume+0x1d/0x50
> >  [<ffffffff810b6718>] async_run_entry_fn+0x48/0x150
> >  [<ffffffff810acc19>] process_one_work+0x1e9/0x5c0
> >  [<ffffffff810acb96>] ? process_one_work+0x166/0x5c0
> >  [<ffffffff810ad038>] worker_thread+0x48/0x4e0
> >  [<ffffffff810acff0>] ? process_one_work+0x5c0/0x5c0
> >  [<ffffffff810b3794>] kthread+0xe4/0x100
> >  [<ffffffff81742672>] ret_from_fork+0x22/0x50
> >  [<ffffffff810b36b0>] ? kthread_create_on_node+0x200/0x200
> > 
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Lyude <cpaul@redhat.com>
> This should be addressed by the connector refcounting fixes Dave Airlie
> has for 4.7 (not all merged yet though). Can you please retest with those?
> -Daniel
> 
> > 
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 6e0d828..252c06c 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -15945,6 +15945,17 @@ void intel_display_resume(struct drm_device *dev)
> >  	dev_priv->modeset_restore_state = NULL;
> >  
> >  	/*
> > +	 * With MST, the number of connectors can change between suspend
> > and
> > +	 * resume, which means that the state we want to restore might now
> > be
> > +	 * impossible to use since it'll be pointing to non-existant
> > +	 * connectors.
> > +	 */
> > +	if (state->num_connector != dev->mode_config.num_connector) {
> > +		drm_atomic_state_free(state);
> > +		state = NULL;
> > +	}
> > +
> > +	/*
> >  	 * This is a cludge because with real atomic modeset
> > mode_config.mutex
> >  	 * won't be taken. Unfortunately some probed state like
> >  	 * audio_codec_enable is still protected by mode_config.mutex, so
> > lock
> > -- 
> > 2.5.5
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx