Kernelnewbies Digest, Vol 71, Issue 22

Sukanya Ch sukanya.c at vvdntech.in
Wed Oct 19 01:33:41 EDT 2016


Hi Wenda Ni,

Please go through the following link to enable debugging output.Seems you
have missed enabling DEBUG in Makefile. Hope it will help you.

https://www.kernel.org/doc/local/pr_debug.txt

*CFLAGS_[filename].o := -DDEBUG*





*With Best Regards,*

Sukanya Ch

Software Engineer

VVDN Technologies Pvt Ltd

*Cell : *+91 9551955031 | *Skype :* sukanya.chinthamreddy


On Tue, Oct 18, 2016 at 7:44 PM, <kernelnewbies-request at kernelnewbies.org>
wrote:

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> Today's Topics:
>
>    1. kernel loglevel (Wenda Ni)
>    2. Re: kernel loglevel (Wenda Ni)
>    3. Re: kernel loglevel (Joel Fernandes)
>    4. Re: kernel loglevel (Thibaut SAUTEREAU)
>    5. Re: kernel loglevel (Wenda Ni)
>    6. Fw: TPS65910 Regulator Isuue (Amit Mahadik)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 17 Oct 2016 19:17:32 -0400
> From: Wenda Ni <wonda.ni at gmail.com>
> Subject: kernel loglevel
> To: kernelnewbies at kernelnewbies.org
> Message-ID:
>         <CAEnvTt0RRDWtMD=VxVpuhiiJ+MRX2g3WiTgXkA-M5GGaTMyB-g@
> mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Dear all,
>
> I am working on a kernel module that incorporate both pr_debug and
> pr_warn. I would like to see pr_debug messages from dmesg.
>
> What I followed is to specify kernel parameter by saying "loglevel=7".
> This can be seen confirmed  from /proc/cmdline. But still, I donot get
> pr_debug level messages either from dmesg or from /var/log/messages. I
> also tried echo 7 > /proc/sys/kernel/printk. It does not return what I
> expect, either.
>
> Let me know what I am missing. Thank you very much in advance.
>
> Cheers,
>
> Wenda Ni, Ph.D.
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 17 Oct 2016 19:47:14 -0400
> From: Wenda Ni <wonda.ni at gmail.com>
> Subject: Re: kernel loglevel
> To: Thibaut SAUTEREAU <thibaut.sautereau at telecom-sudparis.eu>
> Cc: kernelnewbies at kernelnewbies.org
> Message-ID:
>         <CAEnvTt3oh+tuhKCwho8eZd5VmJfuXdcmWGpUpsji
> H2wWSFpWvg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Thank you so much, Thibaut. I have spotted the source-code logic in
> include/linux/prink.h
>
> Cheers,
>
> Wenda Ni, Ph.D.
>
>
>
> On Mon, Oct 17, 2016 at 7:41 PM, Thibaut SAUTEREAU <
> thibaut.sautereau at telecom-sudparis.eu> wrote:
> > On Mon, Oct 17, 2016 at 07:17:32PM -0400, Wenda Ni wrote:
> >> Dear all,
> >>
> >> I am working on a kernel module that incorporate both pr_debug and
> >> pr_warn. I would like to see pr_debug messages from dmesg.
> >>
> >> What I followed is to specify kernel parameter by saying "loglevel=7".
> >> This can be seen confirmed  from /proc/cmdline. But still, I donot get
> >> pr_debug level messages either from dmesg or from /var/log/messages. I
> >> also tried echo 7 > /proc/sys/kernel/printk. It does not return what I
> >> expect, either.
> >>
> >> Let me know what I am missing. Thank you very much in advance.
> >>
> >> Cheers,
> >>
> >> Wenda Ni, Ph.D.
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> > Hello Wenda,
> >
> > I encountered the same issue a while ago.
> > As stated here: http://elinux.org/Debugging_by_printing
> > pr_debug is replaced with an empty statement unless the kernel is
> compiled
> > with DEBUG. So if you just want to play with printing kernel debug logs,
> > just define the DEBUG macro in your module source file for testing.
> >
> > I also observed that without a new line character at the end of the
> string
> > passed to pr_debug, I could not find the log line in dmesg output. Not
> sure
> > where this comes from.
> >
> > --
> > Thibaut SAUTEREAU
> -------------- next part --------------
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>
> ------------------------------
>
> Message: 3
> Date: Mon, 17 Oct 2016 16:48:46 -0700
> From: Joel Fernandes <agnel.joel at gmail.com>
> Subject: Re: kernel loglevel
> To: Wenda Ni <wonda.ni at gmail.com>
> Cc: "kernelnewbies at kernelnewbies.org"
>         <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAD=GYpb-UKodnqeb0o71KytF_M2pLGV7bRzZ3YL4Ck0GqLdU+A@
> mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Hi Wenda,
>
> pr_debug needs you to define the DEBUG macro to activate it.
>
> Check:
> http://stackoverflow.com/questions/28936199/pr-debug-not-giving-any-output
>
> and the kernel docs,
> https://www.kernel.org/doc/local/pr_debug.txt
>
> Joel
>
> On Mon, Oct 17, 2016 at 4:17 PM, Wenda Ni <wonda.ni at gmail.com> wrote:
> > Dear all,
> >
> > I am working on a kernel module that incorporate both pr_debug and
> > pr_warn. I would like to see pr_debug messages from dmesg.
> >
> > What I followed is to specify kernel parameter by saying "loglevel=7".
> > This can be seen confirmed  from /proc/cmdline. But still, I donot get
> > pr_debug level messages either from dmesg or from /var/log/messages. I
> > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I
> > expect, either.
> >
> > Let me know what I am missing. Thank you very much in advance.
> >
> > Cheers,
> >
> > Wenda Ni, Ph.D.
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
> ------------------------------
>
> Message: 4
> Date: Tue, 18 Oct 2016 01:41:57 +0200
> From: Thibaut SAUTEREAU <thibaut.sautereau at telecom-sudparis.eu>
> Subject: Re: kernel loglevel
> To: Wenda Ni <wonda.ni at gmail.com>
> Cc: kernelnewbies at kernelnewbies.org
> Message-ID: <20161017234156.GB1191 at mines-telecom.fr>
> Content-Type: text/plain; charset="utf-8"
>
> On Mon, Oct 17, 2016 at 07:17:32PM -0400, Wenda Ni wrote:
> > Dear all,
> >
> > I am working on a kernel module that incorporate both pr_debug and
> > pr_warn. I would like to see pr_debug messages from dmesg.
> >
> > What I followed is to specify kernel parameter by saying "loglevel=7".
> > This can be seen confirmed  from /proc/cmdline. But still, I donot get
> > pr_debug level messages either from dmesg or from /var/log/messages. I
> > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I
> > expect, either.
> >
> > Let me know what I am missing. Thank you very much in advance.
> >
> > Cheers,
> >
> > Wenda Ni, Ph.D.
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> Hello Wenda,
>
> I encountered the same issue a while ago.
> As stated here: http://elinux.org/Debugging_by_printing
> pr_debug is replaced with an empty statement unless the kernel is compiled
> with DEBUG. So if you just want to play with printing kernel debug logs,
> just define the DEBUG macro in your module source file for testing.
>
> I also observed that without a new line character at the end of the string
> passed to pr_debug, I could not find the log line in dmesg output. Not sure
> where this comes from.
>
> --
> Thibaut SAUTEREAU
> -------------- next part --------------
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> ------------------------------
>
> Message: 5
> Date: Mon, 17 Oct 2016 20:29:33 -0400
> From: Wenda Ni <wonda.ni at gmail.com>
> Subject: Re: kernel loglevel
> To: Joel Fernandes <agnel.joel at gmail.com>
> Cc: "kernelnewbies at kernelnewbies.org"
>         <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAEnvTt0BmAJ_nxf0oEUsFqqJjGssuXCQBg6pdt95Jk
> 3PyBBQew at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Joel,
>
> It works by specifying ccflags-y += -DDEBUG in the Makefile.
>
> Thank you for the info!!!!
>
>
> Cheers,
>
> Wenda Ni, Ph.D.
>
>
> On Mon, Oct 17, 2016 at 7:48 PM, Joel Fernandes <agnel.joel at gmail.com>
> wrote:
>
> > Hi Wenda,
> >
> > pr_debug needs you to define the DEBUG macro to activate it.
> >
> > Check:
> > http://stackoverflow.com/questions/28936199/pr-debug-
> not-giving-any-output
> >
> > and the kernel docs,
> > https://www.kernel.org/doc/local/pr_debug.txt
> >
> > Joel
> >
> > On Mon, Oct 17, 2016 at 4:17 PM, Wenda Ni <wonda.ni at gmail.com> wrote:
> > > Dear all,
> > >
> > > I am working on a kernel module that incorporate both pr_debug and
> > > pr_warn. I would like to see pr_debug messages from dmesg.
> > >
> > > What I followed is to specify kernel parameter by saying "loglevel=7".
> > > This can be seen confirmed  from /proc/cmdline. But still, I donot get
> > > pr_debug level messages either from dmesg or from /var/log/messages. I
> > > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I
> > > expect, either.
> > >
> > > Let me know what I am missing. Thank you very much in advance.
> > >
> > > Cheers,
> > >
> > > Wenda Ni, Ph.D.
> > >
> > > _______________________________________________
> > > Kernelnewbies mailing list
> > > Kernelnewbies at kernelnewbies.org
> > > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
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> ------------------------------
>
> Message: 6
> Date: Tue, 18 Oct 2016 14:11:41 +0000 (UTC)
> From: Amit Mahadik <amitmahadik35 at yahoo.com>
> Subject: Fw: TPS65910 Regulator Isuue
> To: Kernelnewbies <kernelnewbies at kernelnewbies.org>
> Message-ID: <1865063607.2350837.1476799901899 at mail.yahoo.com>
> Content-Type: text/plain; charset="utf-8"
>
>
>
>
> Hi,? ? ?I am working on integrating TPS695190 regulator code into kernel
> version 4.4.16. The regulator powers MMC card slot using Designware MMC
> controller. I have declared the necessary code in my board.c file. The MMC
> card slot is powered by ldo8 supply declared as
> ------------------------------------------------------------
> -----------------Code---------------------------------------
> ------------------------------------------
>
> static struct regulator_consumer_supply opv5xc_ldo8_supply[] = {
> ??????? REGULATOR_SUPPLY("sd_vdd", NULL),
> };
>
> static struct regulator_init_data opv5xc_ldo8 = {
> ??????? .constraints = {
> ??????????????? .min_uV = 1000000,
> ??????????????? .max_uV = 3300000,
> ??????????????? .valid_ops_mask = (REGULATOR_CHANGE_VOLTAGE |
> ??????????????????????????????? REGULATOR_CHANGE_STATUS),
> ??????????????? .boot_on = 1,
> ??????? },
> ??????? .num_consumer_supplies = ARRAY_SIZE(opv5xc_ldo8_supply),
> ??????? .consumer_supplies = opv5xc_ldo8_supply,
> };
> static struct tps65910_board tps65910_pdata = {
> ????? ??????? .tps65910_pmic_init_data[TPS65911_REG_LDO8]???? =
> &opv5xc_ldo8,
> };
> static struct i2c_board_info __initdata opv5xc_i2c1_devs[] = {
> ??????? {
> ??????????????? I2C_BOARD_INFO ("tps65911", TPS65910_I2C_ID1),
> ??????????????? .platform_data = &tps65910_pdata,
> ??????? },
> };
> ------------------------------------------------------------
> ------------------------------------------------------------
> -----------------------------------------------
> When I call regulator_get struct regulator *sd_vdd = regulator_get(NULL,
> "sd_vdd");? function from the Designware MMC driver code function the
> kernel panics.I have attached the log file for reference. Can somebody
> please let me know what I am doing wrong here?
> Regards,Amit.
>
>
>
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> ------------------------------
>
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>
> End of Kernelnewbies Digest, Vol 71, Issue 22
> *********************************************
>
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