From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Jon Hunter <jonathanh@nvidia.com>,
Thierry Reding <thierry.reding@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@kernel.org>
Subject: Re: [PATCH printk v3 2/2] printk/nbcon: Change nbcon_irq_work to IRQ_WORK_LAZY
Date: Tue, 01 Sep 2026 11:59:32 +0206 [thread overview]
Message-ID: <8733vt8fhf.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <20260901093245.344455-3-john.ogness@linutronix.de>
On 2026-09-01, John Ogness <john.ogness@linutronix.de> wrote:
> Change the nbcon_irq_work to be IRQ_WORK_LAZY, thus not raising
> an IRQ upon irq_work queuing. The irq_work is then handled on the
> next kernel tick. This additional delay is acceptable because
> nbcon_irq_work is only responsible for non-emergency deferred
> printing, which is delayed anyway. This has the benefit of not
> needing to raise an IRQ for each printk() call.
>
> On a side note, the Tegra20 and Tegra30 platforms can hang if an
> irq_work IRQ is raised while entering cpuidle states. This problem
> was reproducible by calling printk() while entering cpuidle. So
> this change also provides a workaround for these platforms (as long
> as they are not running tickless).
>
> Link: https://lore.kernel.org/lkml/f3757a75-0ba1-4558-bf57-f19ab7e59a4c@nvidia.com
> Fixes: 76f258bf3f2a ("printk: nbcon: Introduce printer kthreads")
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
Sorry, I failed to gather the previous tags:
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
next prev parent reply other threads:[~2026-09-01 9:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-01 9:31 [PATCH printk v3 0/2] nbcon irq_work fixes John Ogness
2026-09-01 9:31 ` [PATCH printk v3 1/2] printk/nbcon: Flush nbcon_irq_work in nbcon_free() John Ogness
2026-09-02 9:06 ` Petr Mladek
2026-09-01 9:31 ` [PATCH printk v3 2/2] printk/nbcon: Change nbcon_irq_work to IRQ_WORK_LAZY John Ogness
2026-09-01 9:53 ` John Ogness [this message]
2026-09-02 10:02 ` [PATCH printk v3 0/2] nbcon irq_work fixes Petr Mladek
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