February 2011 - kernelnewbies@kernelnewbies.org

SRIO maintenance read hangs (mpc8548)
by shrikant hegde Aug. 4, 2011

Aug. 4, 2011

Hi all, I am working on srio; When i tried to send maintenance packet to switch it hangs. Symptom when i tried to read DIDCAR of switch,( i.e read 0x8000_0000 ), or HDIDLOCK (0x8000_0068 ), execution of code hangs; if i press break in code warrior its coming out with an error. register value dump EPWISR 0x80000000 -- physical or logical/transport error interrupt LTLEDCSR 0x08000000 -- illegal transaction decode, received request/response packet LTLCCCSR 0x82000000 Below are my system detail: Processor mpc8548 and Tsi578 switch. Processor is connected to switch on same board.I have written standalone code (no OS) to exercise srio, using code warrior. Processor side configurations Its configured to 1x, 2.5gbs, host. law and tlb are configured. 0x8000_0000 0x8FFF_FFFF maintenance window configured 0x8000_0000 0x8000_0FFF (4k) switch side configuration 1x,2.5gbs, swap disabled (configured during POR) Processor side link training bit is setting. Am I missing any configuration , in switch side or processor side ? Any pointer is very helpful. Forgive me if its a wrong forum to post srio queries. thanks shrikant -- View this message in context: http://old.nabble.com/SRIO-maintenance-read-hangs-%28mpc8548%29-tp30949266p… Sent from the kernelnewbies mailing list archive at Nabble.com.

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How to verify block numbers of file ?
by kashish bhatia March 8, 2011

March 8, 2011

Is there any method/command/utility to know what are the block numbers which are allocated to a file in ext2 fs? -- Regards, Kashish

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Regarding threaded irq
by anish singh March 4, 2011

March 4, 2011

I have a touch driver which is not yet using threded_irq.So i am planning to change it to use threaded_irq. In the current handler they are first disabling the irq line and then calling the single threaded workqueue to do the rest of the task and when the task is completed i.e. in the end of workqueue function they are enabling the irq line. So my question is if i change it to use threaded_irq.In the handler should i also enable or disable the irq as is done in the case of present handler OR i don't need to do this step? ---i think IRQF_ONESHOT will do this for me right? I want this threaded handler to be executing as soon as possible as i want the latency between the touch by the user and response to be minimum.Is there any way to achieve this? FYI... handler contains some I2C transfer + reporting co-ordinates to Input core. Does the above usecase justify changing to threaded_irq??

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Any tool under linux to parsing BPB/Bs/FAT table?
by loody March 3, 2011

March 3, 2011

Dear all: I recently trace FS/fat and I want to know is there any utility under linux that can help us to easily parse BPB/BS or FAT tables? appreciate your help, miloody

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To schedule a process?
by kashish bhatia March 2, 2011

March 2, 2011

Suppose if I wrote a simple c program but I want to execute this program everyday at a specific time ( say at 12 p.m) . Is there any command by which I can schedule the execution of any process(a.out in this case)? -- Regards, Kashish

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Re: Problem with PCI Driver on Ubuntu 10.10 i386
by Murali N March 1, 2011

March 1, 2011

Hi, On Wed, Feb 23, 2011 at 2:12 PM, Adhyas Avasthi <adhyas(a)gmail.com> wrote: > Hi Murali > > Thanks for the response. Sorry, I should have sent dmesg output earlier. > Yes, the module is loaded in lsmod. > Here is the additional output from dmesg after I inserted the module. > > - Adhyas > > On Wed, Feb 23, 2011 at 11:50 AM, Murali N <nalajala.murali(a)gmail.com> wrote: >> Hi, >> >> On Wed, Feb 23, 2011 at 12:10 PM, Adhyas Avasthi <adhyas(a)gmail.com> wrote: >>> I am trying to develop a very basic PCI device driver for a dummy >>> device I have created in qemu. The device has no functionality except >>> that it sits on the PCI bus behind two bridges (bridge 0 on root bus, >>> bridge 1 only device behind bridge 0, and device behind bridge 1 as >>> the only device). It is a single function do nothing device with one >>> MMIO BAR of 0x10000 size. The BAR is initialized by the kernel at some >>> MMIO location but the device is not disabled, as there is no driver. I >>> have used one of the available vendor ids for my work. >>> >>> My driver is not loaded automatically, so I load the driver manually >>> after the boot of the VM, and then issues a rescan of the entire PCI >>> bus using "echo 1 > /sys/bus/pci/rescan", but nothing happens. The >>> probe function of my driver is never invoked, neither does the device >>> gets visible in lspci output. >>> >>> Can someone help me identify what I might be doing wrong? >>> >>> I have attached the driver code, the lspci output, the lspci -H1 >>> output, the lspci -H1 -xxx -s 02:02.0 output that details the >>> registers of the device. >>> >>> -- >>> Adhyas >>> ******************************************************************** >>> Two types have compatible type if their types are the same. >>> — ANSI C Standard, 3.1.2.6. >>> ******************************************************************** >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies(a)kernelnewbies.org >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>> >>> >> >> Once you loaded manually, did you see any errors in dmesg while >> inserting the module? >> what is the output of 'lsmod'? is your driver present in the list? >> >> Can you please post the dmesg after you loaded the module manually. >> >> -- >> Regards, >> Murali N >> > > > > -- > Adhyas > ******************************************************************** > Two types have compatible type if their types are the same. > — ANSI C Standard, 3.1.2.6. > ******************************************************************** > i am suspecting the 'dummy_pci_tbl' values. How did you populate the device table? #define DUMMY_VENDOR_ID 0xFFF0 #define DUMMY_DEVICE_ID 0x8748 #define DUMMY_CLASS_ID 0x0880 // ?? these values are specific to PCI device which is already on your system? Finally please include MODULE_LICENSE("GPL"); to remove the taint errors. -- Regards, Murali N

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Errors in booting a new image built
by SADA SIVA REDDY S Feb. 28, 2011

Feb. 28, 2011

Hi All, I am trying to setup linux development environment. I did the following steps to get my first work environment. 1. Used my Laptop Dell Inspiron N5030 : (Pentium R Dual Core T4500) 2. Downloaded Ubuntu 10.10 and installed with partition options given by Ubuntu. Now its a dual boot operating system. 3. Installed Git and pulled the source code using instructions at http://linux.yyz.us/git-howto.html#download_first_time (git pull git:// git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git ) 4. Now did make config ( let the default options take except for selecting processor type) 5. Now I built the kernel using 'make -j8 bzImage 6. Copied the image to /boot/newkernel 7. Updated the /boot/grub/grub.cfg to take another menu entry , image pointing to /boot/newkernel. 8. Removed initrd - which should be specific to distributions. When I boot this image , I get an error saying can not open root device.( https://picasaweb.google.com/sadasiva.reddy/KernelError?authkey=Gv1sRgCOLo_… ) Could any one please guide me how to setup this root file system or any thing else that I need to do to be able to boot this kernel that I build. Appreciate your help in this regard. I understand that my knowledge or initial groundwork is not a lot. Pardon my ignorance as I am a new starter to the Linux Kernel world. Thanks, SADA

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Re: make with argument 0 is failing some where
by Tapas Mishra Feb. 28, 2011

Feb. 28, 2011

On Sat, Sep 18, 2010 at 6:06 PM, Tapas Mishra <mightydreams(a)gmail.com> wrote: > On Sun, Sep 12, 2010 at 10:56 AM, Tapas Mishra <mightydreams(a)gmail.com> wrote: > >> >> For the sake of simplicity I am rewriting all the steps that I did >> >> Step 1) copied the config from /boot to $HOME/linux-2.6 >> Step 2) yes ' ' | make O=$HOME/btc oldconfig >> Step 3) make O=$HOME/btc >> got errors >> >> make O=$HOME/btc > Ok finally I have been able to fix this. > To do so what I was trying > I executed make mrproper at two places > one is $HOME/linux-2.6 > and another was $HOME/btc > now I was in > Step 1) cd $HOME/linux-2.6 > Step 2) make mrproper > Step 3) cd $HOME/btc > Step 4) make $O=$HOME/btc mrproper > Step 5) cd $HOME/linux-2.6 > Step 6) copied the config from /boot to $HOME/linux-2.6 > Step 7) yes ' ' | make O=$HOME/btc oldconfig > upto here is all Ok. > Next step is > Step 8) make mrproper > Step 9) cd $HOME/btc > Step 10) make O=$HOME/btc > > and then make with all modules install and rest of the stuff had worked. > -- Though It is an old thread but I wanted to update today I needed it because of a similar error. In above step 8 and step 6 are wrong.When you do a make mrproper to which ever directory you basically are deleting the config generated or you saved. That means if you did following 1) Download the kernel and untar 2) cp /boot/config-whatever /to/directory/which/will/be/argument/of/O then 3) make O=$HOME/btc mrproper then you deleted the config in step 2. Also for make O=$HOME/btc menuconfig to work .config should be in $HOME/btc and not in $HOME/linux-2.6 as I mentioned above in step6.That was a mistake.

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Re: Linux support for Samsung S3C2510A Processor
by spinlock cp Feb. 28, 2011

Feb. 28, 2011

On Mon, Feb 28, 2011 at 3:30 PM, Madhavi Manchala <madhavi.linux(a)gmail.com>wrote: > On Mon, Feb 28, 2011 at 2:53 PM, spinlock cp <spinlock.cp(a)gmail.com> > wrote: > > > > > > On Mon, Feb 28, 2011 at 2:15 PM, Madhavi Manchala < > madhavi.linux(a)gmail.com> > > wrote: > >> > >> Dear All, > >> > >> Does Linux kernel supports the Samsung S3C2510A processor? Why am I > >> asking this question is, when I looked into the arch/arm/ directory I > >> did not find any thing which is related to Samsung S3C2510A processor. > >> There are other directories like mach-s3c24xx and mach-s3c64xx > >> directories, but not mach-s3c25xx. > >> > >> I checked this in 2.6.37 kernel version which is a stable one. > > > > > > Hi Madahvi > > > > Is S3C2510A is an ARM based core ? Linux does not specicallly support > the > > processor family that you've askd for. For list of supported architetucte > > you can refer to this link > > http://en.wikipedia.org/wiki/List_of_Linux_supported_architectures > > Hi Spinlock, > > OK. The Linux supports the ARM architecture. That is true. Then, why > they mentioned different directories under arch/arm directory like > mach-s3c2400, mach-s3c2410, mach-s3c2412, mach-s3c2440, mach-s3c2442, > etc. Then, no need to mention all these sub directories in that arch/arm > directory. Am I correct? mach-s3c2400 , mach-s3c2410 etc are part of Samsung S3C24XX seeirs - ARM 9 based family. Each of these folder contains platform specific code. The corresponding hearder files are located in include/asm-asrm/plat-s3c24xx directories. > Please think once. May be we need to > add some files which are necessary for S3C2510A processor in the > arch/arm/ directory in the form of something like a directory name > s3c2510a. What do you say? > > Yes, you're right , you willl need a platform specific port for S3C2510A. I'm not sure S3C25XX based port is avialble or not. It would also be helpful to you , if you can go through this chapter from , Linux kernel doucmentation. http://lxr.linux.no/#linux+v2.6.37/Documentation/arm/Samsung-S3C24XX/Overvi… The Section 3 should be able to give you more insight. > Thanks and Regards, > Madhavi M. > > > ~Spinlock > >> > >> Please sugget me. > >> > >> Thanks and Regards, > >> Madhavi M. > >> > >> _______________________________________________ > >> Kernelnewbies mailing list > >> Kernelnewbies(a)kernelnewbies.org > >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > Regards Spinlock

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Thread scheduling in 2.6 kernels
by Mandeep Sandhu Feb. 28, 2011

Feb. 28, 2011

Hi Guys, I'm posting on this list after a very long time...so plz excuse me if my question is OT. I had some doubts on how threads are scheduled in 2.6 kernels. A little background of my "issue" first. We're working in an MIPS based embedded system, running a fairly old Linux 2.6.22 kernel (with vendor provided BSP). We write UI applications on top of this system using QT. One of the applications is a photo-viewer like app which fetches image data from the n/w and displays them on the screen in a grid-like manner. The app shows images in a "paged" manner so going from one page to another requires animating the grid with a new set of images. Now the task of decoding the incoming image data is very CPU intensive and so is the animation part. So we used to see the animation suffer when images (for next page were being decoded). So we though of offloading the decoding part to a low priority thread. The main thread mostly used to do 2 main operations - animation (CPU intensive) and n/w i/o (blocking IO). The decoder thread was given the lowest priority and the main GUI thread was given the highest priority (this is QT thread priority and not pthread priority, but QT internally maps such priorities to OS specific values) This helped improve the animation, but 2 implementations that we tried were giving very different and unexpected results: 1. In our first implementation the decoder thread was always running, i.e it was busy-looping even when there was no data to work on. BUT, we were observing that it was getting a chance to run _only_ when the main thread was idle! So it almost looked like once the main thread finished animating (a CPU intensive task) the other thread was getting a chance to run and we used to see all the enqueued images decoded in a "batch". In this implementation the animation was completely smooth as no decoding operation was hampering it. 2. In our 2nd implementation, since busy looping was not a good idea, we changed the decoder thread to sleep (blocking on a mutex) when there was no job to be done. Surprisingly, in this implementation the animation was suffering again. We could see the decoder thread run in-between the main thread's run (which was animating the UI) which could possibly explain the poor animation performance. So my questions: - In the second implementation, why was the low-priority thread running in-between and while doing a busy-loop caused it ran only when the main thread was idle? One of my colleague suggested that since busy-looping is CPU bound, the kernel might be giving it a "nice" value penalty causing it priority to change dynamically. - Is there still a concept of fixed process timeslices for scheduling of processes? - How can I find out if the kernel supports NPTL (kernel managed threads) or plain old linux threads (user-space managed threads)? I was trying to find out more info about the threads when the app is running (using "ps" etc), but it seems that the most useful options are not available in the busybox ver that I'm using. Any other way to get more thread related info about a running application? And again, sorry if this is OT. Thanks, -mandeep

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