On 08/14/2013 12:51 PM, Joe Perches wrote: > On Wed, 2013-08-14 at 09:40 -0700, Sarah Sharp wrote: >> Hi Xenia, >> >> I'm a bit confused. I thought that debugging messages would be turned >> off by default for a module if CONFIG_DYNAMIC_DEBUG was turned on. When >> I tested your patch to remove the CONFIG_USB_XHCI_HCD_DEBUGGING and just >> use dev_dbg, the messages from the xHCI driver appeared in dmesg by >> default. >> >> That generates a lot of log spew. We can have distros add a boot >> parameter option to turn off debug messages, but that boot parameter is >> limited to 1023 characters. I'm concerned that if more drivers add >> dynamic debugging, the distros will eventually run out of space in the >> dynamic debugging boot parameter. I know Greg was ripping out debugging >> config options in other USB drivers, so this is a bit concerning. >> >> Jason, is there a way within the xHCI driver to say that dynamic >> debugging should be off by default? I've looked through the >> documentation, and I can't find anything like that documented. > #undefine DEBUG > >> I've attached my .config file, in case I have something misconfigured. > Because of: > > drivers/usb/host/Makefile:ccflags-$(CONFIG_USB_DEBUG) := -DDEBUG > > you probably want to turn this off > > CONFIG_USB_DEBUG=y > > when dynamic_debug is on.
They should also be emitted in the case that dynamic_debug is off, but we have set -DDEBUG, right? That was the whole point of enabling them for dynamic debug too - to mirror the behavior of !CONFIG_DYNAMIC_DEBUG case. -Jason > CONFIG_DYNAMIC_DEBUG=y > > This will cause all pr_debug/dev_dbg statements to be > emitted without specific enabling via the dynamic_debug > control file. > > (from include/linux/dynamic_debug.h) > > #if defined DEBUG > #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT > #else > #define _DPRINTK_FLAGS_DEFAULT 0 > #endif > > -- 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/
