On Wed, 17 Jul 2013, Russell King - ARM Linux wrote: > 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?
Yes it does, thanks. > 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
