On Thu, 2012-09-27 at 16:20 +0530, Mahapatra, Chandrabhanu wrote: > On Wed, Sep 26, 2012 at 7:59 PM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote: > > > This doesn't work quite correctly. The problem is in dss.h, where we > > define DEBUG if CONFIG_OMAP2_DSS_DEBUG_SUPPORT is set. The thing is, > > DEBUG should be defined before including the kernel headers where the > > pr_debug etc are defined. > > > > So if you try the patches without dynamic debugging enabled, you won't > > get any debug outputs at all, even if CONFIG_OMAP2_DSS_DEBUG_SUPPORT is > > set. > > > > And for dynamic debug, the Kconfig help says: > > > > If a source file is compiled with DEBUG flag set, any > > pr_debug() calls in it are enabled by default, but can be > > disabled at runtime as below. Note that DEBUG flag is > > turned on by many CONFIG_*DEBUG* options. > > > > So if we have CONFIG_OMAP2_DSS_DEBUG_SUPPORT set, all the pr_debugs > > should be enabled by default, which is not the case, again because DEBUG > > is defined too late. > > > > I think setting DEBUG in dss.h should be removed, and instead DEBUG > > should be set in the makefile if CONFIG_OMAP2_DSS_DEBUG_SUPPORT is set. > > > > Tomi > > > > Well the documentation lags in describing about the DEBUG flag. I > should have checked DYNAMIC_DEBUG in Kconfig and pr_debug definition > in printk.h file. > > #if defined(CONFIG_DYNAMIC_DEBUG) > /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */ > #define pr_debug(fmt, ...) \ > dynamic_pr_debug(fmt, ##__VA_ARGS__) > #elif defined(DEBUG) > #define pr_debug(fmt, ...) \ > printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) > #else > #define pr_debug(fmt, ...) \ > no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) > #endif > > As per the definition above pr_debug is dynamic with > CONFIG_DYNAMIC_DEBUG set or else with DEBUG set it is just a normal > kernel debug printk as you have mentioned. > I still don't get how even if DEBUG is set before DSSDBG() is defined > in dss.c pr_debug() fails to enable. Because printk.h is included without DEBUG, thus pr_debug is defined as no_printk. > Well anyways, how to do the same in the Makefile? I tried adding > ccflags-$(CONFIG_OMAP2_DSS_DEBUG_SUPPORT) += -DEBUG > to makefile in dss directory but of no use. -D option for the compiler is used to set defines. So it should be -DDEBUG Tomi
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