From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9568B24DD07; Thu, 3 Jul 2025 11:46:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751543169; cv=none; b=NvgCntIOehWnWjPJ+41aX1bAxLDGsYZrjQdHHbBe4m0oc1emPrqGacgPMgDUJh0yK78uf37ZLnBUjy/CRGuFt9QK4GpvtUDiZnUBr0JrGv0a0/BpETRtrOKgf2U8IP9WkGTX9G70lKmVVCvTRbQo7450bDVIHPOKC9EGmckymdI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751543169; c=relaxed/simple; bh=2k11KvoMBeQIvrAWZA7P5gWj9h1H7/1T5f53ZD8lUOM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qpNjrKrInjTExdTO9XV+834QPUZTVTB7DeWg1yMgXEfu6eH+X6WsQ7JKn2/+9/9I4lenZbSCu+OYRvGvdrfInPgHKNEFYK51LtLyscpC/6BUKKiqzlJaVLPJBWLi0vujQTXYOSm1iKN2C+cftBholPK4vdaicBvvFkjCmYjSSIo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AD9DF1596; Thu, 3 Jul 2025 04:45:45 -0700 (PDT) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B5B1E3F6A8; Thu, 3 Jul 2025 04:45:59 -0700 (PDT) Date: Thu, 3 Jul 2025 12:45:57 +0100 From: Leo Yan To: Breno Leitao Cc: cov@codeaurora.org, rmk+kernel@armlinux.org.uk, mark.rutland@arm.com, catalin.marinas@arm.com, linux-serial@vger.kernel.org, rmikey@meta.com, linux-arm-kernel@lists.infradead.org, usamaarif642@gmail.com, linux-kernel@vger.kernel.org, paulmck@kernel.org Subject: Re: arm64: csdlock at early boot due to slow serial (?) Message-ID: <20250703114557.GD1039028@e132581.arm.com> References: <20250702172036.GC1039028@e132581.arm.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Jul 03, 2025 at 03:02:39AM -0700, Breno Leitao wrote: [...] > > In some cases, if normal world and secure world share the same UART > > port, it can cause the UART state machine malfunction and long wait. > > I don't know how to check it for sure, but, looking at the serial > console output, I don't see anything else using the UART. The only > output I see on the console at that time is coming from linux kernel. > > Would you recommend any additional check? I have no experience in the driver, I should avoid any noise. But two things in my head for quick trying. - First, you could try earlycon mode, e.g., add option in kernel command line: earlycon=pl011,mmio32,0xc280000 earlycon=pl011,0xc280000 This would be possible to give more printing logs. If earlycon works well, then the issue might be caused by later init code (clock, or UART driver itself). - Try another UART port if this is possible. Just curious, you mentioned you are working on the mainline kernel. If you can confirm a workable kernel version, then this info can help to rule out hardware issue and we can review the delta changes. Thanks, Leo