Date:   Tue, 16 Nov 2021 16:39:24 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     Joe Korty <joe.korty@concurrent-rt.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Clark Williams <williams@redhat.com>,
        Jun Miao <jun.miao@windriver.com>,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5.10-rt+] drm/i915/gt: transform irq_disable into
 local_lock.
Message-ID: <20211116163924.5d5a2ffd@gandalf.local.home>
In-Reply-To: <20211116210249.t3f6gw56iaow57mq@linutronix.de>
References: <20211007165928.GA43890@zipoli.concurrent-rt.com>
        <20211007171929.hegwwqelf46skjyw@linutronix.de>
        <20211009164908.GA21269@zipoli.concurrent-rt.com>
        <20211116152534.122f8357@gandalf.local.home>
        <20211116210249.t3f6gw56iaow57mq@linutronix.de>
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On Tue, 16 Nov 2021 22:02:49 +0100
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> On 2021-11-16 15:25:34 [-0500], Steven Rostedt wrote:
> > I'm looking to see what needs to be added to 5.10-rt. Is there a particular
> > fix in one of the 5.x-rt trees (x > 10) that I can pull from? Or is this
> > only an issue with 5.10 and below?  
> 
> I have this:
>   https://lore.kernel.org/all/20211026114100.2593433-1-bigeasy@linutronix.de
> 
> pending vs upstream and I *think* more than just that one (2/9 from the
> series) needs to be backported here. We do have 1/9 differently in 5.10,
> not sure about 4/9.
> I would love more feedback here from people and I tried to motivate Joe
> to provide some. Clark was so nice to test these patches and provide
> feedback. My i915 does not trigger all the code paths I'm touching
> there.
> 
> If you think that 2/9 is obvious enough, please go ahead. If you start
> touching that irq_work area then you might also want to pick
>   810979682ccc9 ("irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.")
>   b4c6f86ec2f64 ("irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT")
>   09089db79859c ("irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT")
> 
> which made their way into v5.16-rc1.
>

I have a few boxes with i915, that maybe could help in testing.

I'll take a look.

-- Steve