From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E15E5202C5D; Tue, 17 Jun 2025 11:42:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750160527; cv=none; b=dEnlp2G0xzXRHaIIQGmnC0zY+94QNpCZuZTrQ/c7LG8IlgGLCDjwcrcN2Rb+nwXg60JHK5OGYQo0WHR8J1gcMICPiHmPOEb2WgkkovfQOEc7r/K6BjP4EWiS/fQlg/jNY8ABoeNnTYcKi0morpG9eSOC7q9OaUN/t1UhvsNM8mg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750160527; c=relaxed/simple; bh=lOwm9sI0KP7rL93Un/JNFyYB8Kf8ajV3HnbE+/qfiBE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I3VvFfeojGvNYPQfR27RMdCfJbo8khrOqrFdWUsy3Lso3WquiuMyKpLOOGcyOdlPi0IXZAXAa6jmNQtmr7odpYxa7z2w9m3VCIu/NX02jsCXVvQyVD7NjXOZ73RXYwlUpEiDEmNdi0b/d2g3dig/dIQhiJaoXTtDtZ+n9PNjA9s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=v68wUDbK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="v68wUDbK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F436C4CEE3; Tue, 17 Jun 2025 11:42:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750160526; bh=lOwm9sI0KP7rL93Un/JNFyYB8Kf8ajV3HnbE+/qfiBE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=v68wUDbK/b7Wqos24oKH/hgR/Q5WDrEmQ4KRbOHAfqO7y9ASMzzVY6e9415zEmuL3 GD+Sx7+9vsPaGTDoVxlQ60j67veVmpRY6PO2KEJWXSfMMn4Ck5bERJDdC806VchCi+ uPiqFqnQ+31VCqlPvFsvVdU/n7vQ0FVSdrDfLy6o= Date: Tue, 17 Jun 2025 13:42:02 +0200 From: Greg Kroah-Hartman To: "Maciej W. Rozycki" Cc: "Jiri Slaby (SUSE)" , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 29/33] serial: 8250: drop DEBUG_AUTOCONF() macro Message-ID: <2025061733-pushy-croon-08da@gregkh> References: <20250611100319.186924-1-jirislaby@kernel.org> <20250611100319.186924-30-jirislaby@kernel.org> 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 Tue, Jun 17, 2025 at 12:32:48PM +0100, Maciej W. Rozycki wrote: > On Wed, 11 Jun 2025, Jiri Slaby (SUSE) wrote: > > > DEBUG_AUTOCONF() is always disabled (by "#if 0"), so one would need to > > recompile the kernel to use it. And even if they did, they would find > > out it is broken anyway: > > error: variable 'scratch' is used uninitialized whenever 'if' condition is false > > This is removing useful debugging aids. How can it be "useful" if it's broken and no one has ever reported that? > The issue with compilation is related to commit 3398cc4f2b15 ("serial: > 8250: Add IIR FIFOs enabled field properly"), which removed the assignment > of IIR to `scratch' (although a path did exist before it that bypassed the > assignment anyway), and can be trivially fixed by bringing the assignment > back and moving the debug statement next to it. So it's been broken for over 2 years and no one has asked for it to be fixed? > I agree that "#if 0" isn't very useful as it requires patching the source > to activate; changing it to "#ifdef DEBUG" would make more sense nowadays. No, dynamic debugging is the proper solution, not build-time stuff. If you really need/want this, add it back in that way, not this old-style "let's rebuild the whole kernel" type of thing. This isn't the 1990's anymore :) thanks, greg k-h