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Date:   Wed, 26 Aug 2020 10:12:11 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Daniel Wagner <wagi@monom.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [ANNOUNCE] v5.9-rc2-rt1
Message-ID: <20200826081211.bvk5kfuzh4vlbh5k@linutronix.de>
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On 2020-08-26 10:08:02 [+0200], Daniel Wagner wrote:
> Hi Sebastian,
Hi,

> On Mon, Aug 24, 2020 at 05:46:05PM +0200, Sebastian Andrzej Siewior wrote:
> > I'm pleased to announce the v5.9-rc2-rt1 patch set.
>=20
> I gave it a quick run on my test system. Can't boot the system at this
> point. Didn't look closer at it, maybe it's something obvious...

Carsten reported it the other day, but didn't Cc: the list. I've sent
him this to test:

diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/=
i915/display/intel_sprite.c
index 24baa5f2047bb..cc435d0a51215 100644
--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -118,8 +118,6 @@ void intel_pipe_update_start(const struct intel_crtc_st=
ate *new_crtc_state)
 			"PSR idle timed out 0x%x, atomic update may fail\n",
 			psr_status);
=20
-	local_lock_irq(&crtc->pipe_update_lock);
-
 	crtc->debug.min_vbl =3D min;
 	crtc->debug.max_vbl =3D max;
 	trace_intel_pipe_update_start(crtc);
@@ -143,11 +141,7 @@ void intel_pipe_update_start(const struct intel_crtc_s=
tate *new_crtc_state)
 			break;
 		}
=20
-		local_unlock_irq(&crtc->pipe_update_lock);
-
 		timeout =3D schedule_timeout(timeout);
-
-		local_lock_irq(&crtc->pipe_update_lock);
 	}
=20
 	finish_wait(wq, &wait);
@@ -180,7 +174,6 @@ void intel_pipe_update_start(const struct intel_crtc_st=
ate *new_crtc_state)
 	return;
=20
 irq_disable:
-	local_lock_irq(&crtc->pipe_update_lock);
 }
=20
 /**
@@ -218,8 +211,6 @@ void intel_pipe_update_end(struct intel_crtc_state *new=
_crtc_state)
 		new_crtc_state->uapi.event =3D NULL;
 	}
=20
-	local_unlock_irq(&crtc->pipe_update_lock);
-
 	if (intel_vgpu_active(dev_priv))
 		return;
=20

He complained about a stale label and so.=20
The RT patch replaced a local-irq-disable with a local-lock which broke.
I intend to get rid of this local-irq-disable on RT, the local-lock is
just duct-tape to make it look the same. If this works for everyone then
I will think of something=E2=80=A6

> Thanks,
> Daniel

Sebastian