Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755976Ab3GQPSc (ORCPT ); Wed, 17 Jul 2013 11:18:32 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:37276 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755676Ab3GQPSa (ORCPT ); Wed, 17 Jul 2013 11:18:30 -0400 Date: Wed, 17 Jul 2013 16:18:16 +0100 From: Russell King - ARM Linux To: Stefano Stabellini Cc: Ian Campbell , Arnd Bergmann , patches@linaro.org, Julien Grall , linux-kernel@vger.kernel.org, Olof Johansson , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm: choose debug/uncompress.h include when uncompress debug is disabled Message-ID: <20130717151816.GN24642@n2100.arm.linux.org.uk> References: <1373897706-15331-1-git-send-email-julien.grall@linaro.org> <20130717151148.GM24642@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130717151148.GM24642@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2880 Lines: 70 On Wed, Jul 17, 2013 at 04:11:48PM +0100, Russell King - ARM Linux wrote: > On Wed, Jul 17, 2013 at 02:25:38PM +0100, Stefano Stabellini wrote: > > On Mon, 15 Jul 2013, Julien Grall wrote: > > > Even if uncompress debug is disabled, some board will continue to print > > > information during uncompress step. > > > > Are you talking about DEBUG_UNCOMPRESS? > > Should I read the sentence as "even if DEBUG_UNCOMPRESS is not selected, > > some board will continue to print information during the uncompress step"? > > > > Isn't this a bug in the platform specific code that should be fixed anyway? > > Hang on, let's be clear what's going on here. > > 1. The normal output from the decompressor is *not* debugging. By that > I mean the "Uncompressing kernel... done" message. That is part of > user output. > > 2. In non-multiplatform environments, the decompressor will normally use > the putc/flush functions found in arch/arm/mach-*/include/mach/uncompress.h > to implement its output, irrespective of the DEBUG_UNCOMPRESS setting. > (An interesting point is that DEBUG_UNCOMPRESS really should depend on > MULTIPLATFORM so that this point is explicit - the option requires > MULTIPLATFORM to be set.) > > 3. DEBUG_UNCOMPRESS allows the functions which we've implemented for LL > debug to be re-used for decompressor output. > > 4. When DEBUG_UNCOMPRESS is not set in a multiplatform kernel, the > decompressors putc() and flush() functions are stubbed out. > > So, it's quite right that you get output from the decompressor even when > DEBUG_UNCOMPRESS is not set. There's no problem with that. Does this patch help to explain this? arch/arm/Kconfig.debug | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index e401a76..583f4a0 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -804,9 +804,19 @@ config DEBUG_LL_INCLUDE config DEBUG_UNCOMPRESS bool - default y if ARCH_MULTIPLATFORM && DEBUG_LL && \ - !DEBUG_OMAP2PLUS_UART && \ + depends on ARCH_MULTIPLATFORM + default y if DEBUG_LL && !DEBUG_OMAP2PLUS_UART && \ !DEBUG_TEGRA_UART + help + This option influences the normal decompressor output only for + multiplatform kernels. Normally, multiplatform kernels disable + decompressor output because it is not possible to know where to + send the decompressor output. + + When this option is set, the selected DEBUG_LL output method + will be re-used for normal decompressor output on multiplatform + kernels. + config UNCOMPRESS_INCLUDE string -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/