April 2011 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

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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Not able to see all the symbols in the output of "nm" command
by Madhavi Manchala June 10, 2011

June 10, 2011

Dear All, I build the OpenWRT image for my target device. I am able to see the "vmlinux" image in trunk/build_dir/linux-s3c2510/linux-2.6.36 directory where linux-s3c2510 indicates my target device. I am NOT able to see some of the function names (symbols), which I developed, in the output of the "nm" command for vmlinux image. Am I missing any thing while building the image for getting all the symbols into the image? I am NOT able to see all the function names which are defined in arch/arm/plat-samsung/include/uncompress.h file. Please let me know if I am missing any thing. Thanks for your suggestions / hints. Thanks and Regards, Madhavi M.

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question about misc char devices, and relationship with udev
by Robert P. J. Day May 5, 2011

May 5, 2011

(probably a question with a very simple answer, i just don't know what it is.) i'm currently trying to document the use of the "misc" char driver to quickly and conveniently create a character driver. there's a decent explanation of misc drivers in the book "essential linux device drivers", as well as a nice example here: http://virtlog.com/2008/03/25/linux-miscdevice-sample/ but here's where i get confused. what a misc char driver does is combine a lot of what you'd normally do in creating a regular char driver in a single call. on page 160 of ELDD, it's explained that a single call to misc_register() does all of the following that you would normally have to do yourself for a regular char driver: * allocates major/minor number via alloc_chrdev_region() * creates /dev and /sys nodes via call to class_device_create() * registers itself as a char driver using cdev_init() and cdev_add() sure enough, i compiled that sample misc char driver (called "mymisc"), loaded it and got an entry for that module both under /sys and under /dev, where i now have the device file: crw------- 1 root root 10, 56 2011-04-23 08:18 /dev/mymisc but here's the confusing part. who or what created that /dev entry? i always thought that was the job of udev, but i never added any udev rule for this new driver. so how did that new /dev file come to be? is there some sort of generic udev rule that would have handled this? also, the ELDD book claims that misc_register() calls the kernel routine class_device_create(). i'm looking at the entire kernel implementation for misc drivers in drivers/char/misc.c, and what i see is a call to device_create() instead. i suspect i should start following the flow of control here, but i'm still curious as to how that /dev file came into existence without any obvious help from udev. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

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need help with my first device driver
by Prashant Shah May 3, 2011

May 3, 2011

Hi, I am trying to write a comedi (drivers/staging/comedi) based driver for the National Instruments USB 6008 USB based data acquisition card. I have created a basic but more simpler structure for the drivers based on usbdux driver which are already present. I have got to the point where the device is detected and drivers are loaded. The /dev/comedi0 device file is created. I am unable to deal with the data transfer. When I try to run xoscope that is used to read the output from the card - the card freezes (the status lights stop blinking). Output from the lsusb : https://github.com/prashants/temptest/blob/8e81e7fb4ea260fa24e68f43c185d768… Source of the driver : https://github.com/prashants/temptest/blob/8e81e7fb4ea260fa24e68f43c185d768… Device : http://sine.ni.com/nips/cds/view/p/lang/en/nid/201986 I am not interested in the digital input/output and analog output at this point. My main concern is the ability to read the analog input. ---------------------------------------------------- Apr 29 14:56:43 prashant kernel: [ 1503.900700] usb 2-1.2: new full speed USB device using ehci_hcd and address 6 Apr 29 14:56:43 prashant kernel: [ 1504.172214] comedi: version 0.7.76 - http://www.comedi.org Apr 29 14:56:43 prashant kernel: [ 1504.174688] comedi: ni_usb6008: init_ni_usb6008 Apr 29 14:56:43 prashant kernel: [ 1504.174692] ni_usb6008: v2.4:Stirling/ITL USB-DUX -- Bernd.Porr(a)f2s.com Apr 29 14:56:43 prashant kernel: [ 1504.174708] comedi: ni_usb6008: ni_usb6008_probe Apr 29 14:56:43 prashant kernel: [ 1504.174711] comedi_: ni_usb6008_: finding a free structure for the usb-device Apr 29 14:56:43 prashant kernel: [ 1504.174959] comedi0: ni_usb6008: has been successfully initialised. Apr 29 14:56:43 prashant kernel: [ 1504.174990] usbcore: registered new interface driver ni_usb6008 Apr 29 14:56:43 prashant kernel: [ 1504.176558] comedi: ni_usb6008: ni_usb6008_firmware_request_complete_handler Apr 29 14:56:43 prashant kernel: [ 1504.176592] comedi: ni_usb6008: ni_usb6008_attach Apr 29 14:56:43 prashant kernel: [ 1504.176593] comedi0: ni_usb6008 0 is attached to comedi. Apr 29 14:56:43 prashant kernel: [ 1504.176595] comedi0: ni_usb6008: attached to ni_usb6008. Apr 29 14:56:43 prashant kernel: [ 1504.176634] comedi_: ni_usb6008_: comedi_usb_auto_config: 0 Apr 29 14:56:47 prashant kernel: [ 1508.563459] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.563466] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.563468] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.563474] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.563475] comedi: ni_usb6008: ni_usb6008_ai_cmd Apr 29 14:56:47 prashant kernel: [ 1508.563477] comedi0: ni_usb6008: sending commands to the usb device: size=8 Apr 29 14:56:47 prashant kernel: [ 1508.563478] comedi: ni_usb6008: send_dux_commands Apr 29 14:56:47 prashant kernel: [ 1508.563631] comedi: ni_usb6008: ni_usb6008_submit_InURBs Apr 29 14:56:47 prashant kernel: [ 1508.563983] comedi: ni_usb6008: ni_usb6008_ai_cancel Apr 29 14:56:47 prashant kernel: [ 1508.563985] comedi: ni_usb6008: ni_usb6008_ai_stop Apr 29 14:56:47 prashant kernel: [ 1508.563986] comedi: ni_usb6008: ni_usb6008_unlink_InURBs Apr 29 14:56:47 prashant kernel: [ 1508.573486] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.573490] comedi0: ni_usb6008: unlinking. Apr 29 14:56:47 prashant kernel: [ 1508.573492] comedi: ni_usb6008: ni_usb6008_ai_stop Apr 29 14:56:47 prashant kernel: [ 1508.573514] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.573517] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.573520] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.573524] comedi: ni_usb6008: ni_usb6008_ai_cmdtest Apr 29 14:56:47 prashant kernel: [ 1508.573526] comedi: ni_usb6008: ni_usb6008_ai_cmd Apr 29 14:56:47 prashant kernel: [ 1508.573528] comedi0: ni_usb6008: sending commands to the usb device: size=8 Apr 29 14:56:47 prashant kernel: [ 1508.573530] comedi: ni_usb6008: send_dux_commands Apr 29 14:56:47 prashant kernel: [ 1508.573750] comedi: ni_usb6008: ni_usb6008_submit_InURBs Apr 29 14:56:47 prashant kernel: [ 1508.583433] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.583435] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.585428] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.585431] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.587422] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.587424] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.589419] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.589420] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.591427] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.591430] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.593412] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:47 prashant kernel: [ 1508.593414] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:47 prashant kernel: [ 1508.595412] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq .... .... .... Apr 29 14:56:51 prashant kernel: [ 1512.572562] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:51 prashant kernel: [ 1512.574550] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:51 prashant kernel: [ 1512.574552] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:51 prashant kernel: [ 1512.576550] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:51 prashant kernel: [ 1512.576551] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:51 prashant kernel: [ 1512.578543] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:51 prashant kernel: [ 1512.578545] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:51 prashant kernel: [ 1512.580543] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:51 prashant kernel: [ 1512.580545] comedi0: ni_usb6008: copying data to transfer_buffer Apr 29 14:56:51 prashant kernel: [ 1512.581218] comedi: ni_usb6008: ni_usb6008_ai_cancel Apr 29 14:56:51 prashant kernel: [ 1512.581220] comedi: ni_usb6008: ni_usb6008_ai_stop Apr 29 14:56:51 prashant kernel: [ 1512.581221] comedi: ni_usb6008: ni_usb6008_unlink_InURBs Apr 29 14:56:51 prashant kernel: [ 1512.582537] comedi: ni_usb6008: ni_usb6008_ai_IsocIrq Apr 29 14:56:51 prashant kernel: [ 1512.582539] comedi0: ni_usb6008: unlinking. Apr 29 14:56:51 prashant kernel: [ 1512.582541] comedi: ni_usb6008: ni_usb6008_ai_stop Apr 29 14:56:55 prashant kernel: [ 1515.973856] usb 2-1.2: USB disconnect, address 6 Apr 29 14:56:55 prashant kernel: [ 1515.973922] comedi: ni_usb6008: ni_usb6008_disconnect Apr 29 14:56:55 prashant kernel: [ 1515.973985] comedi_: ni_usb6008: ni_usb6008_detach Apr 29 14:56:55 prashant kernel: [ 1515.973988] comedi0: ni_usb6008: detach usb device Apr 29 14:56:55 prashant kernel: [ 1515.973991] comedi0: ni_usb6008: detach: successfully removed Apr 29 14:56:55 prashant kernel: [ 1515.974036] comedi: ni_usb6008: tidy_up Apr 29 14:56:55 prashant kernel: [ 1515.974040] comedi_: ni_usb6008: disconnected from the usb

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question regarding SYSCALL macros
by Sudheer Divakaran April 29, 2011

April 29, 2011

Hi, I was going through the file kernel/time.c and found the definition of 'gettimeofday' system call as follows. SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, struct timezone __user *, tz) <--- NOTE THE COMMA between variable types and names. In syscalls.h I could find the needed macros for expanding the definition to its final form i.e., asmlinkage long sys_gettimeofday(struct timeval __user * tv, struct timezone __user *tz) [syscalls.h macros] #define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__) #define SYSCALL_DEFINEx(x, sname, ...) \ __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) #define __SYSCALL_DEFINEx(x, name, ...) \ asmlinkage long sys##name(__SC_DECL##x(__VA_ARGS__)) #define __SC_DECL1(t1, a1) t1 a1 #define __SC_DECL2(t2, a2, ...) t2 a2, __SC_DECL1(__VA_ARGS__) [Question] Note the comma between the variable types and names in the original definition (e.g., "struct timeval __user *, tv" instead of "struct timeval __user *tv"). What is is the reason behind separating variable types and variable names using 'comma' and latter removing the comma character using _SC_DECLx macros? -- Thanks Sudheer

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dma_alloc_from_coherent
by Gang Lei (雷刚) April 29, 2011

April 29, 2011

HI: Can anybody point out that from which pool that function will allocate coherent memory for DMA use? I checked the function source code, the comments is as follow: This function should be only called from per-arch dma_alloc_coherent() * to support allocation from per-device coherent memory pools. * * Returns 0 if dma_alloc_coherent should continue with allocating from * generic memory areas, or !0 if dma_alloc_coherent should return @ret. Can anyone elaborate it? What’s per-device coherent memory pools, when are those pools setup and how? Thanks a lot! Rick lei

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Enabling tickless kernel feature in ARM
by Vikram Narayanan April 28, 2011

April 28, 2011

Hi, I want to enable the dynamic tick aka tickless kernel feature for the BSP which I am developing. What are all the architecture dependent changes that needs to be done for implementing it. There was one struct by the name dyn_tick_timer, which is located under linux/include/asm-arm/mach/time.h file. (which is removed from v 2.6.27) Now my question is that, are all the dyn_tick_timer functionalities are moved to a generic interface somewhere? Are the clock source and clockevent device timers enough to take care of the tickless feature? - Vikram

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Double buffer support in Framebuffer?
by siqiao chen April 28, 2011

April 28, 2011

Hello, Could I ask how do I enable double buffer support in FrameBuffer device? I think I could manually increase xres_virtual/yres_virtual to 2 times of the display size in video driver and swap xoffset/yoffset after VSync. But could I know if this is the right way to do double buffering or this function is already built-in? Thank you! Philip Chen

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quiet compile kernel
by loody April 28, 2011

April 28, 2011

Hi all: I found the compile message of kernel is quite succinct, when we set V=0, and I try to make my project output as clean as kernel did. Then I traced the Makefile and it just define "quiet" and "Q" then export it. Where is the exact place that quiet build begin? Is that complicated to copy this quiet-build process? -- Thanks for your help, miloody

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Staging git tree
by Ezequiel García April 28, 2011

April 28, 2011

Hi everyone, I would like to know where can I find the most recently added staging patches. I heard something about Greg's tree, but I'm not sure wich git tree is it. Also, I would like to ask how can different people work on staging without agreeing on it. I mean, what if I start correcting staging/foo coding style but someone is already working on it ?

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