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Tue, 05 May 2026 06:55:05 -0700 (PDT) Received: from pathway.suse.cz ([176.114.240.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a8eb72a17sm369040085e9.6.2026.05.05.06.55.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2026 06:55:04 -0700 (PDT) Date: Tue, 5 May 2026 15:54:57 +0200 From: Petr Mladek To: Randy Dunlap Cc: linux-kernel@vger.kernel.org, Steven Rostedt , John Ogness , Sergey Senozhatsky , Andrew Morton , bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] printk: remove BOOT_PRINTK_DELAY config Message-ID: References: <20260503214214.3475670-1-rdunlap@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260503214214.3475670-1-rdunlap@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260505_065508_006316_A5F1E8DA X-CRM114-Status: GOOD ( 13.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun 2026-05-03 14:42:14, Randy Dunlap wrote: > This boot option is ancient and probably not being used. > Dave Jones used it successfully maybe 15 years ago... > AFAIK it doesn't work reliably, especially on SMP. I agree that it most likely does not have many users and is not reliable. In addition, it was kind of obsoleted by printk_delay() which does very similar thing except that it can only be set at runtime via sysctl. Which brings an idea. What about doing the obsoleting properly? I mean to: 1. Add "printk_delay" early_param() which would allow to set "printk_delay_msec" via command line. 2. Modify boot_delay_setup() to set "printk_delay_msec" as well. In addition, it might print a message that it has been obsoleted by "printk_delay" and will be removed. Would you mind to do it this way, please? Regarding the reliability, it might get improved by moving the delay to console handling code. It would even allow to use sleeping wait when the consoles are handled in kthreads. But the wait might get multiplied when more consoles are registered and proceed on the same CPU. Anyway, this is out of scope for this patch. Best Regards, Petr