[v2,0/8] drm/i915: PREEMPT_RT related fixups.

Message ID	20240613102818.4056866-1-bigeasy@linutronix.de (mailing list archive)
Headers	show Return-Path: <intel-gfx-bounces@lists.freedesktop.org> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: Jani Nikula <jani.nikula@linux.intel.com>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com>, Thomas Gleixner <tglx@linutronix.de>, Tvrtko Ursulin <tursulin@ursulin.net> Subject: [PATCH v2 0/8] drm/i915: PREEMPT_RT related fixups. Date: Thu, 13 Jun 2024 12:20:17 +0200 Message-ID: <20240613102818.4056866-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: list Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>
Series	drm/i915: PREEMPT_RT related fixups. \| expand [v2,0/8] drm/i915: PREEMPT_RT related fixups. [v2,1/8] drm/i915: Use preempt_disable/enable_rt() where recommended [v2,2/8] drm/i915: Don't disable interrupts on PREEMPT_RT during atomic updates [v2,3/8] drm/i915: Don't check for atomic context on PREEMPT_RT [v2,4/8] drm/i915: Disable tracing points on PREEMPT_RT [v2,5/8] drm/i915/gt: Use spin_lock_irq() instead of local_irq_disable() + spin_lock() [v2,6/8] drm/i915: Drop the irqs_disabled() check [v2,7/8] drm/i915/guc: Consider also RCU depth in busy loop. [v2,8/8] Revert "drm/i915: Depend on !PREEMPT_RT."

Message ID

20240613102818.4056866-1-bigeasy@linutronix.de (mailing list archive)

Headers

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: intel-gfx@lists.freedesktop.org,
	intel-xe@lists.freedesktop.org
Cc: Jani Nikula <jani.nikula@linux.intel.com>,
 Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
 Rodrigo Vivi <rodrigo.vivi@intel.com>,
 Thomas Gleixner <tglx@linutronix.de>, Tvrtko Ursulin <tursulin@ursulin.net>
Subject: [PATCH v2 0/8] drm/i915: PREEMPT_RT related fixups.
Date: Thu, 13 Jun 2024 12:20:17 +0200
Message-ID: <20240613102818.4056866-1-bigeasy@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: list
Errors-To: intel-gfx-bounces@lists.freedesktop.org
Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>

Series

drm/i915: PREEMPT_RT related fixups. | expand

Message

Sebastian Andrzej Siewior June 13, 2024, 10:20 a.m. UTC

Hi,

The following patches are from the PREEMPT_RT queue.  It is mostly about
disabling interrupts/preemption which leads to problems. Unfortunately
DRM_I915_LOW_LEVEL_TRACEPOINTS had to be disabled because it acquires locks
from within trace points. Making the lock a raw_spinlock_t led to higher
latencies during video playback
  https://lore.kernel.org/all/20211006164628.s2mtsdd2jdbfyf7g@linutronix.de/

and I'm not sure if I hit the worse case here.
I tested it on a SandyBridge with built-in i915 by using X, OpenGL and
playing videos without noticing any warnings. However, some code paths
were not entered.
I carry them for some time now and most issues were reported by other
people and they reported that things work for them since.

v1…v2:
  - The tracing disable bits (4/8) have been reworked after Steven pointed out
    that something isn't right.
  - The irq_work() bits have been dropped because they are no longer
    needed.