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Kernel Module Compilation error
by Arun M Kumar April 14, 2014

April 14, 2014

Hi, I get the following error while compiling my very basic kernel Module (a hello world module) * //--------------------------------------------------------------------------------------------------------------* make -C /home/arun/Dev/linux-stable M=/home/arun/Dev/practice/Kmodules modules make[1]: Entering directory `/home/arun/Dev/linux-stable' WARNING: Symbol version dump /home/arun/Dev/linux-stable/Module.symvers is missing; modules will have no dependencies and modversions. CC [M] /home/arun/Dev/practice/Kmodules/Hello_world.o /home/arun/Dev/practice/Kmodules/Hello_world.c:1:0: error: code model 'kernel' not supported in the 32 bit mode /home/arun/Dev/practice/Kmodules/Hello_world.c:1:0: sorry, unimplemented: 64-bit mode not compiled in make[2]: *** [/home/arun/Dev/practice/Kmodules/Hello_world.o] Error 1 make[1]: *** [_module_/home/arun/Dev/practice/Kmodules] Error 2 make[1]: Leaving directory `/home/arun/Dev/linux-stable' make: *** [all] Error 2 *//-----------------------------------------------------------------------------------------------------------------* what could be the possible cause of this error? on my system *$uname -a* returns the following.. *Linux linux-xh55.site 3.4.6-2.10-desktop #1 SMP PREEMPT Thu Jul 26 09:36:26 UTC 2012 (641c197) i686 i686 i386 GNU/Linux*

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APIs to submit bios at block layer
by KASHISH BHATIA April 14, 2014

April 14, 2014

Hi all, Could anyone explain the difference between submit_bio() and generic_make_request() ? How they are different in functionality? How lower layers treat bios submitted via submit_bio() / generic_make_request() ? When is it preferable to use api generic_make_request() than submit_bio() api? -- Regards, Kashish Bhatia

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checkpatch.pl comment style warnings
by Greg Donald April 14, 2014

April 14, 2014

When I run checkpatch.pl -f, it complains about comment blocks like /* * foo * bar */ with "networking block comments don't use an empty /* line, use /* Comment..." But I found this: http://fr.it-usenet.org/thread/18772/41342/, which makes me think that particular checkpatch.pl warning should possibly be ignored for code not in net or drivers/net. 1) Are there different preferred commenting styles for networking code versus everything else? 2) Assuming the comment code above does need fixing, would an example fix be as simple as this? /* foo * bar */ 3) What about the very similar comment blocks checkpatch.pl doesn't currently complain about, do these need fixing too? /** * foo * bar */ Thanks. -- Greg Donald

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Gianfar Ethernet Device Driver used in MPC8641D-HPCN
by Ashish Khetan April 14, 2014

April 14, 2014

Hi, I Have MPC8641D-HPCN based custom designed board and After some changes the Linux 3.14 is now booting on my board. we are using same phy device ie vitesse vsc8244. The Difference between my board and the original board is in only PHY interrupt ie Our custom Designed Board MPC8641D-HPCN original board eTSEC0(mac)----> phy0 ---- irq0 eTSEC0(mac)----> phy0 ---- irq10 eTSEC1(mac)----> phy1 ---- irq1 eTSEC1(mac)----> phy1 ---- irq10 eTSEC2(mac)----> phy2 ---- irq2 eTSEC2(mac)----> phy2 ---- irq10 eTSEC3(mac)----> phy3 ---- irq3 eTSEC3(mac)----> phy3 ---- irq10 After Booting Linux the first Ethernet device is only eTSEC0 is working means at booting time it detects all 4 ports and initialize all ports. The following IP addresses are assigned to each port: interface Board IP Host IP eth0 ---- 192.168.10.2 192.168.10.1 eth1 ---- 192.168.20.2 192.168.20.1 eth2 ---- 192.168.30.2 192.168.30.1 eth3 ---- 192.168.40.2 192.168.40.1 when i Tried to ping from board to host (ie ping 192.168.10.1) through eth0 its pinging. but when i tried to ping from other ports ie eth1, eth2 & eth3 its not pinging and prints "destination host not reachable". Also I tried to ping from pc(ie host) to board same result was printing. Then I started debugging, I put a printk function inside Gianfar.c file and gfar_clean_rx_ring() for printing packet sequence and packet size. I started pinging each port from pc (ie host) and its printing on each reception as: For eth0 [ 94.966113] Packet 1 size 60 [ 95.965588] Packet 2 size 120 [ 97.980729] Packet 3 size 180 [ 98.980705] Packet 4 size 240 [ 99.998872] Packet 5 size 300 and same for other interfaces too. Here is the device tree snap-shot for ethernet which I am using with this kernel (hope may be helpful): enet0: ethernet@24000 { #address-cells = <1>; #size-cells = <1>; cell-index = <0>; device_type = "network"; model = "TSEC"; compatible = "gianfar"; reg = <0x24000 0x1000>; ranges = <0x0 0x24000 0x1000>; local-mac-address = [ 00 00 00 00 00 00 ]; interrupts = <29 2 30 2 34 2>; interrupt-parent = <&mpic>; tbi-handle = <&tbi0>; phy-handle = <&phy0>; phy-connection-type = "rgmii-id"; mdio@520 { #address-cells = <1>; #size-cells = <0>; compatible = "fsl,gianfar-mdio"; reg = <0x520 0x20>; phy0: ethernet-phy@0 { interrupt-parent = <&mpic>; interrupts = <0 1>; reg = <0>; device_type = "ethernet-phy"; }; phy1: ethernet-phy@1 { interrupt-parent = <&mpic>; interrupts = <1 1>; reg = <1>; device_type = "ethernet-phy"; }; phy2: ethernet-phy@2 { interrupt-parent = <&mpic>; interrupts = <2 1>; reg = <2>; device_type = "ethernet-phy"; }; phy3: ethernet-phy@3 { interrupt-parent = <&mpic>; interrupts = <3 1>; reg = <3>; device_type = "ethernet-phy"; }; tbi0: tbi-phy@11 { reg = <0x11>; device_type = "tbi-phy"; }; }; }; enet1: ethernet@25000 { #address-cells = <1>; #size-cells = <1>; cell-index = <1>; device_type = "network"; model = "TSEC"; compatible = "gianfar"; reg = <0x25000 0x1000>; ranges = <0x0 0x25000 0x1000>; local-mac-address = [ 00 00 00 00 00 00 ]; interrupts = <35 2 36 2 40 2>; interrupt-parent = <&mpic>; tbi-handle = <&tbi1>; phy-handle = <&phy1>; phy-connection-type = "rgmii-id"; mdio@520 { #address-cells = <1>; #size-cells = <0>; compatible = "fsl,gianfar-tbi"; reg = <0x520 0x20>; tbi1: tbi-phy@11 { reg = <0x11>; device_type = "tbi-phy"; }; }; }; Is this happening because of phy interrupt or something else? Please through some light on this. how to make it working? how to disable phy interrupt? Does phy interrupt matters for gianfar interrupt or polling mode? Please give some pointer/anything to help more understanding of ethernet driver. Thanks And Regards A$hi$h

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Run a program when DP monitor is plugged in/out
by arun c April 11, 2014

April 11, 2014

Hi, I want to run a program when DP monitor is plugged in/out. My linux kernel ( 3.14.0-00348-gbfcbf45) gets an interrupt when DP cable is removed or inserted. >From the graphics driver interrupt handler I can differentiate the two events. I want to run a user space program when this removal/insertion happens. What are the possible ways to achieve this? when I google for this I am seeing examples related to udev(How to run a script when a usb device is inserted/removed); but in my case it is not device insertion/removal. There is no need for a device creation when the DP monitor is plugged in/out(There is no device node available for me). Basically I want to send this removal/insertion event from my kernel interrupt handler to user space program. Regards, Arun C

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how tso (tcp segmentation offload) effect TCP bidirectional test sending throughput.
by Varun Sharma April 11, 2014

April 11, 2014

Hi, if we off tso (tcp segmentation offload) on sending side , *TCP Bidirectional* test sending throughput decrease as compare to *TCP Unidirectional *test sending throughput . whereas if we on tso(tcp segmentation offload) on sending side , both testgive almost same sending throughput result. is anyone know how tso(tcp segmentation offload) effect TCP Bidirectional sending throughput ? i am using iperf-2.0.5 for this case. Thanks in advance. Regards varun

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Linux hibernation support for loadable drivers
by AYAN KUMAR HALDER April 11, 2014

April 11, 2014

Hi, I am working with the linux hibernation code( swsusp hibernation framework) on an ARM based custom SOC. I am using some drivers like Nand Flash Controller driver as loadable modules. As per my understanding , during hibernation kernel calls suspend for all the drivers while creating a snapshot. During resume, after the kernel resumes the snapshot (from late_initcall - software_resme) , the kernel calls resume for all the drivers. As nand and some other drivers do not support suspend/resume, thus they fail to work on system resume. So is it fine to call driver_unregister/driver_register during hibernation/resume for the drivers which do not support suspend/resume. I do not want the user to manually remove/insert the drivers on suspend/resume. Regards, Ayan Kumar Halder

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Linux hibernation support for loadable drivers
by Ayan Halder April 11, 2014

April 11, 2014

Hi, I am working with the linux hibernation code( swsusp hibernation framework) on an ARM based custom SOC. I am using some drivers like Nand Flash Controller driver as loadable modules. As per my understanding , during hibernation kernel calls suspend for all the drivers while creating a snapshot. During resume, after the kernel resumes the snapshot (from late_initcall - software_resme) , the kernel calls resume for all the drivers. As nand and some other drivers do not support suspend/resume, thus they fail to work on system resume. So is it fine to call driver_unregister/driver_register during hibernation/resume for the drivers which do not support suspend/resume. I do not want the user to manually remove/insert the drivers on suspend/resume. Regards, Ayan Kumar Halder

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Odd Behavior
by Steven Williams April 10, 2014

April 10, 2014

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Last summer I added some more RAM to my computer to find that Linux would no longer boot. Oddly Windows Vista still worked fine. I tried playing with kernel parameters and acpi=off, acpi=rsdt and mem=4G would make it bootable (but mem=4G would only give me 3G of RAM to use). I then noticed that 32 bit Linux wasn't affected, but I would still like to use 64 bit Linux and continue. My problem is that when I would boot those extra parameters it would just reset itself. Lately I have set panic=0, but even then it still reboots. My first question is what is making it reboot? After I installed Sabayon yesterday and was trying to get it to boot, I noticed that after I loaded its themed Grub 2 over Fedora's console Grub 2 I could back out of it and boot Fedora just fine without any of the extra flags. Today I installed the starfield theme and configured it in Fedora's Grub which strangely makes it bootable. I would like to track down the issue and file a bug report to get it fixed, but I am afraid I have insufficient data and I need to prevent the computer from rebooting to see the last error messages. It seems like there are uninitialized values that are crashing it, but I have very little to go on. I have tried using USB to serial to get a serial console logging the output, but it doesn't get any messages even though after boot I can send plain text through the cable no problem. Netconsole has also not worked, and no log files are written before it crashes. Any ideas for getting more information to get this fixed are appreciated. - -- Steven Williams Student at Ouachita Hills College My PGP Keyhttp://pgp.mit.edu/pks/lookup?op=get&search=0xCACA6C74669A54FA -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTRveDAAoJEMrKbHRmmlT64CoQALhjHZ5Cg/VRFdHewlSR/PeL oKb2/2qT0DrfAkeXvIbV+imPiaZaqRNNQmCIk/afNpe+D/LtY+TkL05zOVt0u+Jk /bgsaFIedu9HtsWBAZsxhxjHsr52RD3WIu2vbNXIJF9nJOLv0qwwiOWzkl2d7biu URTrHDL8IfWJLS+w2MkTTPVLXOxsIFmTlIfjJhh0UM+4PwPNC30MXSQbBcsKmqRl ssrVayHW2LCY2QiM/nHhcrsn+PuXq4Le132tr9qjYvPVUxdxmwa25YkkqOupNYtj 1EBqJO8ztVpSZXa6+dy4KIteD2W5uOhHMVdzPDAsAXGgN61aDKfyiBz//ZrB0CsW u/RFNKkbGcuVKrHxbDrP6717b1wOZwHkg8IqEpUqvIUwMBLgpoAuVw64DR7wYEW2 SV82A3Nu/EPgzx5RqvuW0WEmAO478UYV060bh95HtbR5KY+o3CKSBYsUSXN/ccyx JvXJo9k+mmKBX4TNN/q3th6wBF7E9uL8FQh2ANMBrIvxkYMHYK4UoOf9QEBIgTpT kMbsKQGNbruXJACMH18CLr2Lt9Q/DTB1Nz0e0yfGrNZJnpzbfCw68tAdxUeKf0Ft n7r8Pjm5beRNGetqy395DIi81NmwFZULMgaMb26uoNTNU7hlcdim/p7QJI+KBAwN NXOoNwot7gSDMDTgPJr2 =d+UF -----END PGP SIGNATURE-----

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ipv6 multipath (ECMP) routing
by Vasiliy Tolstov April 10, 2014

April 10, 2014

Hi all. I can't find answer in google, does linux 3.12 support ECMP routing vith ipv6? -- Vasiliy Tolstov, e-mail: v.tolstov(a)selfip.ru jabber: vase(a)selfip.ru

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