From akpm@linux-foundation.org Thu Jul 12 22:08:41 2007 From: David Brownell Date: Thu, 12 Jul 2007 22:08:22 -0700 Subject: dev_vdbg(), available with -DVERBOSE_DEBUG To: mm-commits@vger.kernel.org Cc: david-b@pacbell.net, dbrownell@users.sourceforge.net, greg@kroah.com Message-ID: <200707130508.l6D58MP3029707@imap1.linux-foundation.org> From: David Brownell This defines a dev_vdbg() call, which is enabled with -DVERBOSE_DEBUG. When enabled, dev_vdbg() acts just like dev_dbg(). When disabled, it is a NOP ... just like dev_dbg() without -DDEBUG. The specific code was moved out of a USB patch, but lots of drivers have similar support. That is, code can now be written to use an additional level of debug output, selected at compile time. Many driver authors have found this idiom to be very useful. A typical usage model is for "normal" debug messages to focus on fault paths and not be very "chatty", so that those messages can be left on during normal operation without much of a performance or syslog load. On the other hand "verbose" messages would be noisy enough that they wouldn't normally be enabled; they might even affect timings enough to change system or driver behavior. Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/driver.c | 7 ------- include/linux/device.h | 10 ++++++++++ 2 files changed, 10 insertions(+), 7 deletions(-) --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -29,13 +29,6 @@ #include "hcd.h" #include "usb.h" -#define VERBOSE_DEBUG 0 - -#if VERBOSE_DEBUG -#define dev_vdbg dev_dbg -#else -#define dev_vdbg(dev, fmt, args...) do { } while (0) -#endif #ifdef CONFIG_HOTPLUG --- a/include/linux/device.h +++ b/include/linux/device.h @@ -572,6 +572,16 @@ dev_dbg(struct device * dev, const char } #endif +#ifdef VERBOSE_DEBUG +#define dev_vdbg dev_dbg +#else +static inline int __attribute__ ((format (printf, 2, 3))) +dev_vdbg(struct device * dev, const char * fmt, ...) +{ + return 0; +} +#endif + #define dev_err(dev, format, arg...) \ dev_printk(KERN_ERR , dev , format , ## arg) #define dev_info(dev, format, arg...) \