| looking4b | I have noticed that the kernel does some printk very early to print out the banner and version of the kernel. It does this before parsing the kernel command line which tells it which ttyS to use. How does the kernel figure out to which UART/Serial/Console port to send the output of printk at that stage? | 01:29 |
|---|---|---|
| looking4b | I am trying to get the kernel working on my embedded systems but I do not get any serial output from the kernel. When I debug it then I noticed that is calling printk but I do not see anything on my console (serial port) | 01:29 |
| looking4b | can anybody help? | 01:29 |
| looking4b | I am talking of the printks in start_kernel | 01:44 |
| jjohansen | looking4b: those prints use earlyprintk | 02:12 |
| jjohansen | you can set earlyprintk bootargs | 02:12 |
| jjohansen | eg. | 02:12 |
| jjohansen | earlyprintk=serial,ttyBF0,57600 | 02:13 |
| jjohansen | I would need to lookup how it determines which console to use by default | 02:13 |
| looking4b | I think my kernel is using uart0 by default instead of using uart1 which is the one my hardware supports | 02:15 |
| looking4b | I did compiled with a hard coded command line that has dev=ttyS1,115200 | 02:16 |
| looking4b | but I guess the kernel is crashing before it can use those settings | 02:16 |
| looking4b | I do not even know if ttyS1 is really going to use uart1 | 02:16 |
| looking4b | there are 3 uarts in my system | 02:17 |
| looking4b | I've been reading the source code but in some places they use dynamic function pointers to do stuff and I get lost then because I do not know to what function the pointer is pointing to | 02:17 |
| looking4b | Another thing that I would like to know is how to make the System.map give me more details | 02:18 |
| looking4b | right now it tells me a symbol and its address but I also want to know where that symbol is located | 02:18 |
| looking4b | in which file.o the symbol was found | 02:19 |
| looking4b | regularly gcc/ld will spit out a .map file with that information by default but I think System.map is being generating by parsing stuf from the .elf | 02:19 |
| looking4b | I guess at that point finding where the symbol came from cannot be done since all the file.o have been combined | 02:20 |
| jjohansen | looking4b: right, that info isn't available in standard .elf you need the debug information to do that kind of mapping | 02:46 |
| jjohansen | if you know the address you can always map it back using gdb and the debug info | 02:47 |
| jjohansen | I would have to go lookup how again as I haven't done it for a while | 02:47 |
| looking4b | yeah, I do not know why the .map file that gcc/ld spits out is not used as system.map | 02:49 |
| looking4b | it has much more info | 02:49 |
| looking4b | I will have to research how to compile the kernel with debug info on | 02:50 |
| jjohansen | are you using custom builds via make or the kernel build scripts | 02:51 |
| looking4b | the truth is that I am using uCLinux with 2.6 kernel | 02:51 |
| jjohansen | okay | 02:52 |
| looking4b | but I thought it should be the same for any distro | 02:52 |
| looking4b | I guess ubuntu patches the kernel with their own stuff but the basics are the same | 02:53 |
| jjohansen | make CONFIG_DEBUG_INFO=1 | 02:54 |
| jjohansen | that will turn on -g and -gdwarf-2 for the compiler | 02:55 |
| looking4b | thanks | 03:01 |
| looking4b | jjohansen: Adding a -Map=linux.map to the following line in the root Makefile did the trick | 03:44 |
| looking4b | cmd_vmlinux__ ?= $(LD) -Map=linux.map $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \ | 03:44 |
| looking4b | now I see things like 0x40020000 _start | 03:46 |
| looking4b | .head.text 0x40020000 0xde arch/m68knommu/platform/coldfire/head.o | 03:46 |
| looking4b | good to know in which file my entry point is | 03:46 |
| looking4b | seems like my kernel does not get compressed | 03:46 |
| looking4b | i think misc.c decompress the kernel | 03:47 |
| jjohansen | looking4b: nice | 03:51 |
| theRealSaint | dpkg-gencontrol: error: package linux-image-2.6.35-rc5-custom+ not in control info | 07:00 |
| theRealSaint | am getting this error while compiling a vanilla kernel on ubuntu | 07:00 |
| theRealSaint | any pointers? | 07:00 |
| jjohansen | theRealSaint: how are you setting up the vanilla kernel for compile? | 07:07 |
| theRealSaint | git download | 07:08 |
| theRealSaint | am getting this error while compiling a vanilla kernel on ubuntu | 07:08 |
| theRealSaint | fakeroot make-kpkg --initrd --append-to-version=-custom kernel_image kernel_headers | 07:08 |
| theRealSaint | jjohansen, these are the commands | 07:09 |
| achiang | theRealSaint: can you do a grep LOCALVERSION .config | 07:09 |
| theRealSaint | CONFIG_LOCALVERSION="" | 07:10 |
| theRealSaint | auto is not set | 07:10 |
| jjohansen | theRealSaint: hrmm I have never used make-kpkg to do vanilla builds | 07:11 |
| jjohansen | I start with git pull of vanilla and either use plain kernel make, make install, make modules_install, update-initramfs, update-grub | 07:13 |
| achiang | that's what i said earlier in #u-devel. ;) | 07:13 |
| achiang | jjohansen: you forgot make firmware_install. :) | 07:13 |
| jjohansen | or if I want a .deb, copy in the debian, and debian.master files from an ubuntu kernel | 07:13 |
| jjohansen | ah yeah, well you know the basic steps | 07:14 |
| jjohansen | and then I twiddle with configs maybe, and do | 07:14 |
| jjohansen | skipabi=true fakeroot debian/rules binary-generic | 07:15 |
| jjohansen | hrmm well actually I usually need to edit the version strings first, then do | 07:16 |
| jjohansen | fakeroot debian/rules clean | 07:16 |
| jjohansen | fakeroot debain/rules prepare-generic | 07:16 |
| jjohansen | check config, and typing is right, maybe edit debian/change_log to add ~jj to the dpkg version | 07:17 |
| jjohansen | the do | 07:17 |
| jjohansen | fakeroot debian/rules binary-generic | 07:17 |
| theRealSaint | hmm | 07:18 |
| jjohansen | theRealSaint: https://wiki.ubuntu.com/Kernel/Dev/QuickBuildLocal | 07:21 |
| jjohansen | covers the basics of how we build kernels | 07:21 |
| jjohansen | basically all I do is transplant the debian bits from an ubuntu kernel into a vanilla kernel, and then do standard kernel build | 07:22 |
| jjohansen | err standard ubuntu kernel build | 07:22 |
| jk- | apt-get install iprint :) | 09:06 |
| jdstrand | apw: hi! fyi only. I have an i7 running lucid that would not resume from suspend well | 09:20 |
| jdstrand | apw: (usb wouldn't come up) | 09:20 |
| jdstrand | apw: kees and I talked, and though his symptoms were totally different than mine, I decided to blacklist tpm | 09:20 |
| jdstrand | apw: and lo and behold... it works fine | 09:20 |
| jdstrand | apw: kees mentioned you had reports of i7 suspend issues, so I thought I'd pass that along. I'll let you know if anything changes on maverick for me | 09:21 |
| lifeless | apw: jdstrand: I have suspend issues on i7 on mav | 09:31 |
| lifeless | lucid base, maverick kernel, been insanely busy :( | 09:31 |
| jdstrand | lifeless: you might try to do 'lsmod|grep tpm', then rmmod those prior to suspend and see if it works better | 09:32 |
| lifeless | ok, will give that a shot | 09:32 |
| jdstrand | lifeless: I've only done it a few times, but it has worked every time since then. prior to that, it never worked right | 09:33 |
| === persia` is now known as persia | ||
| * abogani waves | 10:19 | |
| abogani | apw, Do you have a chance to review -lowlatency kernel (and -realtime also) before of Alpha-3? | 10:19 |
| vanhoof | sconklin: https://patchwork.kernel.org/patch/108727/ | 10:51 |
| diwic | abogani, out of interest, what differs the -lowlatency kernel from the -preempt kernel? | 10:51 |
| diwic | I'm trying to understand the differences between the different attempts get lower latency... | 10:52 |
| abogani | diwic, https://lists.ubuntu.com/archives/kernel-team/2010-February/008708.html | 11:27 |
| vanhoof | sconklin: updated https://bugs.edge.launchpad.net/ubuntu/+source/linux/+bug/561802 | 13:07 |
| ubot2 | Launchpad bug 561802 in linux (Ubuntu Lucid) (and 1 other project) "[lucid] [i915] blank screen on Latitude E6410 (affects: 24) (heat: 171)" [Medium,In progress] | 13:07 |
| === luftikuss is now known as luftikus2 | ||
| nessita | hi there! can anyone give me a hand with a potential ACPI issue in my toshiba laptop? | 13:43 |
| hazmat | does anyone know any details on the http://events.linuxfoundation.org/linuxcon2010/crawford the KSLM monitoring stuff? most i can find are some irc log messages, and an empty launchpad project | 17:53 |
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