April 2012 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

32 bit kernel on 64 bit machine
by er krishna April 20, 2012

April 20, 2012

Hi All, Is it possible to boot the 64 bit machine through 32 bit compiled kernel ? I tried its compilation on fedora 16 64 bit and intel sandybridge 64 bit with following option: $ make ARCH=i386 menuconfig $ make ARCH=i386 –j4 but it failed to boot. Any suggestion if it can be done by any way. Best Regards, Krishna

2 1

3 way handshake
by Chir0n April 19, 2012

April 19, 2012

Hello, Can someone tell me where I can find out the code snippet that has the 3 way handshake values? Best regards, Chiron

2 2

Re: Doubt
by Mulyadi Santosa April 19, 2012

April 19, 2012

Hi :) I can't help you for that, sorry. It's better if you discuss it further in kernelnewbies. Also, I think there are few basics you need to strengthen first and that might be solely up to you to work on it. On Wed, Apr 18, 2012 at 08:17, Niamathullah Sharief <shariefbe(a)gmail.com> wrote: > Dear Mulyadi, > > I research it but i didn't get an idea. > > Could you please help me to do research in kernel programming? > > Actually i am student of Engineering College. > > As you are my Guru in Linux could you please me? > > I will be very very happy if you help me to do any research. > > Regards > Sharief > > > On Tue, Apr 10, 2012 at 2:17 PM, Niamathullah Sharief <shariefbe(a)gmail.com> > wrote: >> >> Sure Mulyadi, I will let you know about the thing for sure..... >> >> On 4/10/12, Mulyadi Santosa <mulyadi.santosa(a)gmail.com> wrote: >> > Hi :) >> > >> > Wish you luck. And if you have time, you could let me know what you >> > found out later :) >> > >> > On Mon, Apr 9, 2012 at 00:30, Niamathullah Sharief <shariefbe(a)gmail.com> >> > wrote: >> >> Dear mulyadi santosa, >> >> >> >> Thanks for replying my mail... >> >> >> >> I will research it on which you asked me and i will let you know un >> >> detail >> >> soon.... >> >> >> >> Thanks a lot.... >> >> >> >> Regards >> >> Sharief >> >> >> >> On 8 Apr 2012 22:39, "Mulyadi Santosa" <mulyadi.santosa(a)gmail.com> >> >> wrote: >> >>> >> >>> Hi :) >> >>> >> >>> Oh gee, this is the first time someone admit being my fans :) thanks a >> >>> lot for your appreciation :) >> >>> >> >>> Hm, device driver that does I/O? what kind of I/O? reading from block >> >>> device? char device? console? network? >> >>> >> >>> Try to elaborate more .... :) >> >>> >> >>> On Sun, Apr 8, 2012 at 09:25, Niamathullah Sharief >> >>> <shariefbe(a)gmail.com> >> >>> wrote: >> >>> > Dear Mulyadi, >> >>> > >> >>> > This is Sharief from India. I am fan of you. I have some doubt in >> >>> > writing >> >>> > device drivers. >> >>> > >> >>> > I am planning to write an code which can access the I/O. >> >>> > >> >>> > What will be the best approach to do this? >> >>> > >> >>> > Please help me.. >> >>> > >> >>> > Regards >> >>> > Sharief >> >>> >> >>> >> >>> >> >>> -- >> >>> regards, >> >>> >> >>> Mulyadi Santosa >> >>> Freelance Linux trainer and consultant >> >>> >> >>> blog: the-hydra.blogspot.com >> >>> training: mulyaditraining.blogspot.com >> > >> > >> > >> > -- >> > regards, >> > >> > Mulyadi Santosa >> > Freelance Linux trainer and consultant >> > >> > blog: the-hydra.blogspot.com >> > training: mulyaditraining.blogspot.com >> > > > -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

2 1

Can request_firmware be called from a platform_driver ?
by Holmes, Michael A (Mike) April 19, 2012

April 19, 2012

Hi I have a fully working system to which I want to add the request firmware mechanism to an existing platform driver I have working. I instrumented mdev in busybox 1.5.1 and in firmware_class.c 2.6.35 so that I could figure this out. What I see with firmware_request() is that the kernel makes the firmware request and does not find any firmware and mdev sees nothing. However if I change my code to do request_firmare_nowait(), the entire system comes up and about 30seconds in the timeout calls my kernel side continue for request_firmare_nowait() and I DO now see my request handled by mdev, however it is a REMOVE request not the ADD request. All this makes me think that platform drivers exist before the hotplug mechanism is able to operate, is this true ? Many thanks Mike

3 7

BUILD_BUG_ON & __bad_udelay for linux 3.3.2 kernel compile on ARM
by Abhijit Pawar April 19, 2012

April 19, 2012

Hi All, I have compiled the latest linux kernel (3.3.2) (after hearing the provided support of this series after the 2.6 series )for ARM platform on fedora box. I faced couple of problems: 1. BUILD_BUG_ON : There were errors and make stopped for couple of files. The error said , negative type value for array. At this moment, I have just commented the calls. However just wondering what could be potential problem? 2. __bad_udelay After making the above changes, the compilation finished just fine, however doing modpost presented new problems as mentioned below: OBJCOPY arch/arm/boot/zImage Kernel: arch/arm/boot/zImage is ready Building modules, stage 2. MODPOST 2136 modules ERROR: "__bad_udelay" [sound/pci/ali5451/snd-ali5451.ko] undefined! ERROR: "__bad_udelay" [drivers/scsi/atp870u.ko] undefined! ERROR: "__bad_udelay" [drivers/net/ethernet/sun/sungem.ko] undefined! ERROR: "__bad_udelay" [drivers/gpu/drm/radeon/radeon.ko] undefined! ERROR: "__bad_udelay" [drivers/gpu/drm/nouveau/nouveau.ko] undefined! ERROR: "__bad_udelay" [drivers/atm/he.ko] undefined! make[1]: *** [__modpost] Error 1 make: *** [modules] Error 2 I have to go and replace many of the calls for udelay having value greater than 2000 with mdelay(2) or more. So is it that these drivers are not meant for ARM or they are not yet completely supported for ARM? Regards, Abhijit Pawar

1 0

About module priority
by Geraint Yang April 19, 2012

April 19, 2012

Hi folks, I am writing a kernel module for a sd card, but when I insert a sd card into my box, the default sd driver will probe before my driver, and my driver will never have chance to probe. Is there any method to make my driver probe the sd card before the default sd driver? Thanks in advance.

4 7

git pull fails on linux-next (out of memory)
by Arvid Brodin April 19, 2012

April 19, 2012

On 2012-03-06, I cloned linux-next: $ git clone git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git linux-next-20120306 I now want to update this repository before posting patches, to make sure they still apply cleanly. I first tried this on 20120328: $ git pull remote: Counting objects: 63784, done. remote: Compressing objects: 100% (13595/13595), done. remote: Total 45829 (delta 38421), reused 38448 (delta 31414) Receiving objects: 100% (45829/45829), 9.87 MiB | 209 KiB/s, done. Resolving deltas: 100% (38421/38421), completed with 5695 local objects. >From git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next + 5a377dc...bc6f15c akpm-end -> origin/akpm-end (forced update) 055bf38..de8856d akpm-start -> origin/akpm-start + a568b5f...7734592 master -> origin/master (forced update) 055bf38..de8856d stable -> origin/stable * [new tag] next-20120328 -> next-20120328 >From git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next * [new tag] v3.3 -> v3.3 * [new tag] v3.3-rc7 -> v3.3-rc7 warning: too many files (created: 1625 deleted: 423), skipping inexact rename detection warning: too many files (created: 5127 deleted: 1509), skipping inexact rename detection warning: too many files (created: 1134 deleted: 655), skipping inexact rename detection warning: too many files (created: 4816 deleted: 3510), skipping inexact rename detection warning: too many files (created: 1004 deleted: 544), skipping inexact rename detection warning: too many files (created: 1734 deleted: 1778), skipping inexact rename detection warning: too many files (created: 1069 deleted: 608), skipping inexact rename detection warning: too many files (created: 1070 deleted: 764), skipping inexact rename detection warning: too many files (created: 757 deleted: 405), skipping inexact rename detection warning: too many files (created: 980 deleted: 542), skipping inexact rename detection fatal: inflateInit: out of memory (no message) I then "forgot" about it for a little while, doing other stuff. Tried it again today: $ git pull remote: Counting objects: 16816, done. remote: Compressing objects: 100% (1595/1595), done. remote: Total 9491 (delta 7901), reused 9254 (delta 7678) Receiving objects: 100% (9491/9491), 2.53 MiB | 299 KiB/s, done. Resolving deltas: 100% (7901/7901), completed with 3010 local objects. >From git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next + bc6f15c...73bd151 akpm-end -> origin/akpm-end (forced update) de8856d..1c03658 akpm-start -> origin/akpm-start + 7734592...1dc85fe master -> origin/master (forced update) de8856d..1c03658 stable -> origin/stable * [new tag] next-20120330 -> next-20120330 warning: too many files (created: 1625 deleted: 423), skipping inexact rename detection warning: too many files (created: 5127 deleted: 1509), skipping inexact rename detection warning: too many files (created: 1134 deleted: 655), skipping inexact rename detection warning: too many files (created: 4816 deleted: 3510), skipping inexact rename detection warning: too many files (created: 1004 deleted: 544), skipping inexact rename detection warning: too many files (created: 1734 deleted: 1778), skipping inexact rename detection warning: too many files (created: 1069 deleted: 608), skipping inexact rename detection warning: too many files (created: 1070 deleted: 764), skipping inexact rename detection warning: too many files (created: 757 deleted: 405), skipping inexact rename detection warning: too many files (created: 1084 deleted: 773), skipping inexact rename detection warning: too many files (created: 980 deleted: 542), skipping inexact rename detection fatal: Out of memory? mmap failed: Cannot allocate memory $ git gc Counting objects: 2609985, done. Delta compression using up to 2 threads. Compressing objects: 100% (392553/392553), done. Writing objects: 100% (2609985/2609985), done. Total 2609985 (delta 2197683), reused 2602739 (delta 2190459) $ git pull warning: too many files (created: 1625 deleted: 423), skipping inexact rename detection warning: too many files (created: 5127 deleted: 1509), skipping inexact rename detection warning: too many files (created: 1134 deleted: 655), skipping inexact rename detection warning: too many files (created: 4816 deleted: 3510), skipping inexact rename detection warning: too many files (created: 1004 deleted: 544), skipping inexact rename detection warning: too many files (created: 1734 deleted: 1778), skipping inexact rename detection warning: too many files (created: 1069 deleted: 608), skipping inexact rename detection warning: too many files (created: 1070 deleted: 764), skipping inexact rename detection warning: too many files (created: 757 deleted: 405), skipping inexact rename detection warning: too many files (created: 1084 deleted: 773), skipping inexact rename detection warning: too many files (created: 980 deleted: 542), skipping inexact rename detection fatal: Out of memory? mmap failed: Cannot allocate memory $ free total used free shared buffers cached Mem: 998920 309376 689544 0 10200 177252 -/+ buffers/cache: 121924 876996 Swap: 2923788 161956 2761832 $ git --version git version 1.6.3.3 I cannot find anything useful using Google. It's not like I'm doing anything complicated, nor is my machine very low on memory. Do I really have to "re-clone" the repository and re-apply my patches every time I want to keep the repository up-to-date? (I've had the same problem before and used that "solution".) Or is there some other way to do this? Perhaps there is a way to perform the pull a little bit at a time, e.g. pull linux-next-20120313, linux-next-20120320 etc? -- Arvid Brodin Enea Services Stockholm AB - since February 16 a part of Xdin in the Alten Group. Soon we will be working under the common brand Xdin. Read more at www.xdin.com.

4 4

Doubt regarding PageLocked in Linux kernel source
by Shashidhara Shamaiah April 19, 2012

April 19, 2012

Hi, I was looking at the source file fs/jbd/transaction.c . In the function journal_invalidatepage the code calls the macro PageLocked . I need to look at its implementation. I could locate where the definition of PageLocked. Its not a function as its absent in the System.map file. I have searched in internet. It was defined as a macro in older kernels. But I could not get its definition in the recent kernels. Please point me to the right direction. Regards Shashidhara Information transmitted by this e-mail is proprietary to MphasiS, its associated companies and/ or its customers and is intended for use only by the individual or entity to which it is addressed, and may contain information that is privileged, confidential or exempt from disclosure under applicable law. If you are not the intended recipient or it appears that this mail has been forwarded to you without proper authority, you are notified that any use or dissemination of this information in any manner is strictly prohibited. In such cases, please notify us immediately at mailmaster(a)mphasis.com and delete this mail from your records.

2 1

Include guard macro query
by Pritam Bankar April 19, 2012

April 19, 2012

Hi, In Linux code we add a guard macro to avoid multiple declarations of identifiers. But I see some macros defined with trailing underscores. e.g. In arch/x86/include/asm/ Normally it is defined like, #ifndef _ASM_X86_ALTERNATIVE_H #define _ASM_X86_ALTERNATIVE_H But in some files I see trailing underscore after H , e.g. arch/x86/include/asm/intel_scu_ipc.h #ifndef _ASM_X86_INTEL_SCU_IPC_H_ #define _ASM_X86_INTEL_SCU_IPC_H_ There are others files also arch/x86/include/asm/irqflags.h http://lxr.linux.no/#linux+v3.3.2/arch/x86/include/asm/probe_roms.h DOES THIS TRAILING UNDERSCORE HAS SPECIAL MEANING ??? Thanks -- Pritam Bankar

2 1

how to use the memory allocated in kernel?
by 夏业添 April 18, 2012

April 18, 2012

Hi everyone, there are some functions can alloc memory in kernel, but it seems that I cannot use it directly. Here is my code: static int mytest_vm(){ struct vm_struct *v_start; v_start=alloc_vm_area(PAGE_SIZE,NULL); //the kernel api has changed, I don't understand why there is a second parameter if(v_start==NULL){ printk("cannot alloc page\n"); return -1; } sprintf((char *)v_start->addr,"this is a test.\n"); printk("after sprintk:%s",(char *)v_start->addr); free_vm_area(v_start); return 0; } module_init(mytest_vm); but it just got a kernel Oops. Can anyone explain this to me? Thanks very much!

4 5