From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47ACB426689; Fri, 10 Jul 2026 12:34:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783686886; cv=none; b=h25U0rznDC4agp/0EeHisTeVJ3SpY3IILZSxM+bLMoOhjgx324WqZhhGefL/WrQTsHyDwxyPjo6+bvOXVdi9nIwK3HRcxswKKKgBxQdpB1DKnLKy9b5araumCSeRrRE8rfJahGXIs9aIoHE82YfMxEvWg0zu9LfxNw/wVTv4+tM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783686886; c=relaxed/simple; bh=HDTxe6xiRRo69tVt4vRfP07e38SHgjIcfxiImNWIgYs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rwvRtudzynmrJ2Ex2xp+QWoleVJv1Pac2vyYR06I56msjEmSj7ccvwOi2GANmqUjQqta+2/3WOWCqX+Sf5IYPkImoXPqjQcHXlTa8uUJsO1l6pufqKRiV9ksfuSeUtKJMcLPAO9hUMN6WREA3w2qh1gY2E+VpQGHRxngE2g2D5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UfW1YrL3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UfW1YrL3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98EA61F000E9; Fri, 10 Jul 2026 12:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783686883; bh=29r2WDwJmH10NZK24eXPq16WSbuygX+3I1ZV8mJmKUk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=UfW1YrL3NbwajMFFv8vhDVWTssNAUKM3uoYaDldqao5GLe9CBCuT9BMZZmJj+npew OPfgvgjePlIhLXebpyFXGtZudfz0tuNXnGyCLKHRoOFi9F5Ue2GaAaHzpuPupmBWB8 oprBkPuMnEFtNCqYfzlxnFs1SlqDZpCl3T5Dgs/o= Date: Fri, 10 Jul 2026 14:34:39 +0200 From: Greg Kroah-Hartman To: Markus Probst Cc: Jiri Slaby , "Rafael J. Wysocki" , Len Brown , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH v3 2/2] ACPI: SPCR: Support UART clock frequency field Message-ID: <2026071007-amaze-tartly-6282@gregkh> References: <20260615-acpi_spcr-v3-0-9a59ebad74ea@posteo.de> <20260615-acpi_spcr-v3-2-9a59ebad74ea@posteo.de> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260615-acpi_spcr-v3-2-9a59ebad74ea@posteo.de> On Mon, Jun 15, 2026 at 12:40:22AM +0000, Markus Probst wrote: > The Microsoft Serial Port Console Redirection (SPCR) specification > revision 1.08 comprises additional field: UART Clock Frequency [1]. > > It contains a non-zero value indicating the UART clock frequency in Hz. Ok, but then what are we going to do with this? Please make this a lot more descriptive, I have no idea what this is supposed to be doing at all. > > Link: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table [1] > Signed-off-by: Markus Probst > --- > drivers/acpi/spcr.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c > index 73cb933fdc89..c79c809f49d4 100644 > --- a/drivers/acpi/spcr.c > +++ b/drivers/acpi/spcr.c > @@ -228,7 +228,8 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console) > pr_info("console: %s\n", opts); > > if (enable_earlycon) > - setup_earlycon(opts); > + setup_earlycon_with_uartclk(opts, > + table->header.revision >= 3 ? table->uart_clk_freq : 0); Why the magic number 3? thanks, greg k-h