* Printk output on console @ 2004-12-21 6:32 selvakumar nagendran 2004-12-27 10:34 ` Robin Jose 0 siblings, 1 reply; 6+ messages in thread From: selvakumar nagendran @ 2004-12-21 6:32 UTC (permalink / raw) To: linux kernel mailing list How can we see the output of printk calls in kernel source files in our console. Is there any special command or utility for it? How to view the output of printk on our console? What is the log level to be set for this? Thanks, selva __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Printk output on console 2004-12-21 6:32 Printk output on console selvakumar nagendran @ 2004-12-27 10:34 ` Robin Jose 0 siblings, 0 replies; 6+ messages in thread From: Robin Jose @ 2004-12-27 10:34 UTC (permalink / raw) To: selvakumar nagendran; +Cc: linux kernel mailing list You can refer to Rubini's book "Linux Device Drivers 2nd Edition". See section "How messages gets logged" in Chapter 4, which explains in detail how to use printk for debugging. This book is now available online, under Oreilly's open book project http://www.xml.com/ldd/chapter/book/ch04.html Thanks, Robin On Mon, 20 Dec 2004 22:32:22 -0800 (PST), selvakumar nagendran <kernelselva@yahoo.com> wrote: > How can we see the output of printk calls in kernel > source files in our console. Is there any special > command or utility for it? > How to view the output of printk on our console? What > is the log level to be set for this? > > Thanks, > selva > > __________________________________ > Do you Yahoo!? > Take Yahoo! Mail with you! Get it on your mobile phone. > http://mobile.yahoo.com/maildemo > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Printk output on console @ 2004-12-21 9:24 srinivas naga vutukuri 2004-12-21 9:43 ` selvakumar nagendran 0 siblings, 1 reply; 6+ messages in thread From: srinivas naga vutukuri @ 2004-12-21 9:24 UTC (permalink / raw) To: linux-kernel Hi Selva, I understood the question as where all/what all printks (with line nos and the file names) you are looking for is it. I think, in a normal printf using the macros __FILE__ and __LINE__ will give that... ex: printk(KERN_ERR "%s: Driver Initialisation failed", __FILE__); Is this helpful... Regards, srinivas. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Printk output on console 2004-12-21 9:24 srinivas naga vutukuri @ 2004-12-21 9:43 ` selvakumar nagendran 2004-12-21 16:19 ` srinivas naga vutukuri 2004-12-23 11:04 ` Luca Falavigna 0 siblings, 2 replies; 6+ messages in thread From: selvakumar nagendran @ 2004-12-21 9:43 UTC (permalink / raw) To: srinivas naga vutukuri; +Cc: linux-kernel Hi srinivas, My question is "We are having lot more printk statements in the kernel source files. While the kernel is in execution where the output of all these statements will go? and can we redirect the output of printk to our console? Please help me. Also I have one more error after having compiled my new kernel 2.6.9. After booting it shows the following error "Kernel panic syncing unable to mount block(0,0) VFS specify root =LABEL correctly" Do u know how to deal with it? Thanks, selva --- srinivas naga vutukuri <srinivas.vutukuri@gmail.com> wrote: > Hi Selva, > > I understood the question as where all/what all > printks (with > line nos and the file names) > you are looking for is it. I think, in a normal > printf using the > macros __FILE__ and __LINE__ will give that... > > ex: > printk(KERN_ERR "%s: Driver Initialisation failed", > __FILE__); > Is this helpful... > > Regards, > srinivas. > - > To unsubscribe from this list: send the line > "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at > http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Printk output on console 2004-12-21 9:43 ` selvakumar nagendran @ 2004-12-21 16:19 ` srinivas naga vutukuri 2004-12-23 11:04 ` Luca Falavigna 1 sibling, 0 replies; 6+ messages in thread From: srinivas naga vutukuri @ 2004-12-21 16:19 UTC (permalink / raw) To: selvakumar nagendran; +Cc: linux-kernel Hi Selva, You can go through, one of the help link on the log msgs... http://www.hk8.org/old_web/linux/run/ch08_03.htm I think, they(kernel printk's) are directing to the console only... Or you can observe, initially while booting it up, after console initiation happened, it starts buffering out all the printk's output to the console only. But i did't remember, the code flow, at a particular point, the X or something the shell will take over of it...But any emergency msgs, from the kernel, will be coming onto the Console only... I think, for your error msg, you can better google it...Its not able to recognise, the boot partition may be... Regards, srinivas. ----- Original Message ----- From: "selvakumar nagendran" <kernelselva@yahoo.com> To: "srinivas naga vutukuri" <srinivas.vutukuri@gmail.com> Cc: <linux-kernel@vger.kernel.org> Sent: Tuesday, December 21, 2004 3:13 PM Subject: Re: Printk output on console > Hi srinivas, > My question is "We are having lot more printk > statements in the kernel source files. While the > kernel is in execution where the output of all these > statements will go? and can we redirect the output of > printk to our console? > Please help me. Also I have one more error after > having compiled my new kernel 2.6.9. After booting it > shows the following error > > "Kernel panic syncing unable to mount block(0,0) VFS > specify root =LABEL correctly" > Do u know how to deal with it? > > Thanks, > selva > --- srinivas naga vutukuri > <srinivas.vutukuri@gmail.com> wrote: > > > Hi Selva, > > > > I understood the question as where all/what all > > printks (with > > line nos and the file names) > > you are looking for is it. I think, in a normal > > printf using the > > macros __FILE__ and __LINE__ will give that... > > > > ex: > > printk(KERN_ERR "%s: Driver Initialisation failed", > > __FILE__); > > Is this helpful... > > > > Regards, > > srinivas. > > - > > To unsubscribe from this list: send the line > > "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at > > http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > > > > > > __________________________________ > Do you Yahoo!? > Read only the mail you want - Yahoo! Mail SpamGuard. > http://promotions.yahoo.com/new_mail ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Printk output on console 2004-12-21 9:43 ` selvakumar nagendran 2004-12-21 16:19 ` srinivas naga vutukuri @ 2004-12-23 11:04 ` Luca Falavigna 1 sibling, 0 replies; 6+ messages in thread From: Luca Falavigna @ 2004-12-23 11:04 UTC (permalink / raw) To: selvakumar nagendran; +Cc: linux-kernel -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Selvakumar, | While the |> kernel is in execution where the output of all these |> statements will go? printk messages go to /proc/kmsg. You can read them using cat (e.g. cat /proc/kmsg) | can we redirect the output of |> printk to our console? There is another way to display kernel messages on a console: managing ttys. Here is some code (taken from Peter Salzman's "The Linux Kernel Module Programming Guide"): static void print_string(char *str) { struct tty_struct *tty; #if ( LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,5) ) tty = current->tty; #else tty = current->signal->tty; #endif if (!tty) return; ((my_tty->driver)->write) (my_tty, 0, str, strlen(str)); ((my_tty->driver)->write) (my_tty, 0, "\015\012", 2); } Regards, Luca -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iQEVAwUBQcqmKxZrwl7j21nOAQKKegf/ZvQxx4FlaObzfeRQYXr5rRyK3/CSwaMX 3vFxX4fGm1Bn0PkTM1NgmgGnDdWaRFyME4odSy6k5XjnyPwO1DqkDUqJarexaq2V 8wrFhQMe3duEhgxonhOSVn/n+/ZIkqxkLujgk5YNpI8jE2vgzw9SwgGb5ck4wEz3 KbqF7YDRPnPot2rud3RTVVzc1MOb0Ti0zDRMpmvyOxkjOL1eocYKJfo5ZalNBQZi k6B7Akk4zWZ6iFjl2Ojxw4RrZVoUupPb2qbkGWp11ghStTur1Qpw5WJyQ25zQB40 8r8ERFfzE02dbE/jiUj5SucJ8DVIKY38KXcMTS64+vWtH9263GkuxQ== =1DIB -----END PGP SIGNATURE----- ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2004-12-27 10:36 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2004-12-21 6:32 Printk output on console selvakumar nagendran 2004-12-27 10:34 ` Robin Jose 2004-12-21 9:24 srinivas naga vutukuri 2004-12-21 9:43 ` selvakumar nagendran 2004-12-21 16:19 ` srinivas naga vutukuri 2004-12-23 11:04 ` Luca Falavigna
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