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From: Thomas Gleixner <tglx@kernel.org>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org,
	linux-rt-devel@lists.linux.dev
Cc: Krzysztof Kozlowski <krzk@kernel.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Clark Williams <clrkwllms@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] irqchip/exynos-combiner: switch to raw_spinlock
Date: Thu, 21 May 2026 14:31:54 +0200	[thread overview]
Message-ID: <87zf1tueo5.ffs@tglx> (raw)
In-Reply-To: <97f33a9d-5fdd-4766-aaff-d10d5f5fdf28@samsung.com>

On Thu, May 21 2026 at 13:26, Marek Szyprowski wrote:
> On 21.05.2026 11:06, Thomas Gleixner wrote:
>> What is this lock actually protecting?
>>
>> Each combiner has it's own @base address, so there is no concurrency
>> problem between two cascade interrupts being handled at the same time.
>>
>> That means the only possible problem would be that the same cascade
>> interrupt is handled on two CPUs concurrently. Is that even possible?
> Frankly speaking I did this conversion mechanically, late in the evening to fix
> the bug warning I've spotted. Indeed this spinlock looks like a copy&paste or
> development leftover. The only side-effect of it I see is a memory barrier,
> which might affect how the register access happens, but this should not affect
> cascade operation imho. Do You want me to send a patch removing it completely?

I've applied the fixup for now. But, yes please send a removal against

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/urgent

Thanks,

        tglx


      reply	other threads:[~2026-05-21 12:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20260520220432eucas1p10502ca0f9368bd6de5ce027ad8170109@eucas1p1.samsung.com>
2026-05-20 22:04 ` [PATCH] irqchip/exynos-combiner: switch to raw_spinlock Marek Szyprowski
2026-05-21  9:04   ` Sebastian Andrzej Siewior
2026-05-21  9:06   ` Thomas Gleixner
2026-05-21 11:26     ` Marek Szyprowski
2026-05-21 12:31       ` Thomas Gleixner [this message]

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