Hi Drew, Nice to hear from you! You are super smart - no surprise you are part of the foundation 😊 Thank you very much for the support, I will try it out and see where it take me. Stay safe!
Best Regards, Marisol On Fri, Apr 3, 2020 at 1:03 PM Drew Fustini <[email protected]> wrote: > On Thu, Apr 2, 2020 at 2:46 AM Salgado, Marisol <[email protected]> > wrote: > > SDK: ti-processor-sdk-linux-am335x-evm-05.03.00.07. > > Hi Marisol! Nice to see a familiar name from my days at Newark. I'm > part of the BeagleBoard.org Foundation so happy to help where I can. > > Based on am335x in the Subject, are you working with a BeagleBone Black? > > > I want to have more debug ouputs in the console window during the Linux > kernel booting so that I can trace for example MMC driver loading process. > > > > Added some printk() into the kernel, for example printk("this function > is called \n"). After successful compiling and loading the kernel > unfortunately I can't see the > > expected output message "this function is called" in the console window. > > It is generally easier to use the "pr_" helper functions: > https://elinux.org/Debugging_by_printing > > pr_err() uses KERN_ERR level should always print regardless of the > printk log level. KERN_ERR is not a good practice for debug output, > but it does eliminate the chance that the log level is filtering out > your print statements. > > Try adding this: > pr_err("DEBUG: start name_of_function()"); > > If you don't see that in dmesg, then it is likely that the function > you put that in is never actually called. > > > I also tried > > > > echo 8 > /proc/sys/kernel/printk > > > > dmesg > > > > after login but the same results. > > > > Is there any configuration missing in .config file? > > level 8 should be sufficient but it is easier if you just set the > level in the .config before you compile your kernel. > > CONFIG_PRINTK_TIME=y > CONFIG_CONSOLE_LOGLEVEL_DEFAULT=7 > CONFIG_CONSOLE_LOGLEVEL_QUIET=7 > CONFIG_MESSAGE_LOGLEVEL_DEFAULT=7 > > You probably also want to make sure dynamic debugging is enabled: > CONFIG_DYNAMIC_DEBUG=y > > Dynamic debugging is a neat feature where you can chose to see more > debug information for a particular source code file: > > https://linux-kernel-labs.github.io/refs/heads/master/labs/kernel_modules.html?highlight=config_dynamic_debug#dynamic-debugging > > Sometimes you don't even need to add in your own debug print > statements, you just need to enable the dynamic debug output that is > already built-in to a driver or subsystem. > > > I also see brcmf_dbg() in kernel files, how can I activate it? > > Are you trying to debug a Broadcom wifi driver? > > Taking a look at Elixir to search the kernel code: > https://elixir.bootlin.com/linux/latest/ident/brcmf_dbg > > It looks like CONFIG_BRCM_TRACING will enable debug output: > > https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/broadcom/brcm80211/brcmfmac/debug.h#L63 > > Try setting that in your .config: > https://cateee.net/lkddb/web-lkddb/BRCM_TRACING.html > > While it is technically to enable function tracing for the driver, it > looks like it will cause brcmf_dbg() to be defined. > > Now the individual invocations of brcmf_dbg() will have a log level > associated with them. It appears that level can be set as kernel > module parameter: > > https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c#L42 > > This forum post has more information: > https://forum.openwrt.org/t/getting-output-of-brcmf-dbg/31094/4 > > It indicates this can be set while the module is loaded via: > echo 6 > /sys/module/brcmfmac/parameters/debug > > Let me me now how it goes. > > Thanks, > Drew > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CAEf4M_BhJHRyc9xwVC2GFsdmRn0pg0k%3DABc37h2v14EOe_X%2BGg%40mail.gmail.com > . > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHx6sU72MGih-FSHW4%2BY2V1NbkHbq_b0xVUBOwVQ_BA%2BRMGSLg%40mail.gmail.com.
