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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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Disabling an interrupt
by Jacky Lam March 3, 2011

March 3, 2011

Hi, It's long before when I want to enable/disable an interrupt, I call enable_irq()/disable_irq(). However, recently, I do that again. disable_irq() do nothing. I looked into the code and find disable_irq() is pointing to a empty function default_disable(). This change is started from 2.6.20. I want to know what should I do if I want to disable an interrupt now? Thanks. Jacky

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likely kernel/driver problem with 3G USB stick
by Simon Leung March 2, 2011

March 2, 2011

Hi all, I'm having a problem with my 3G USB stick (Huawei E220) . The kernel I'm using is version 2.6.21 customized for an ARM board. When I insert the USB stick into the system, normally 3 device show up: /dev/ttyUSB{0,1,2}. The problem I' having is that some time, only the first one shows up and I cannot connect to it. When this happens, normally a reboot will fix it. As I said, this sounds like a kernel/driver issue to me. Could somebody give me some pointers as how to prove/fix it? Thanks,

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what is the kernel symbol for user space grant access driver
by Tapas Mishra March 2, 2011

March 2, 2011

Hi, I want to know with respect to an image here http://bderzhavets.files.wordpress.com/2010/04/pv-2-6-32-12.png I have already compiled a kernel it mentions to enable "user space grant access driver" While compiling I did not notice it how can I now verify post compile some symbol CONFIG_* which can tell me if I included it? How can I find out can such a thing be looked some where in .config file? --

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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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cudaram - a block device exposing nvidia gpus ram implemented with cuda
by Piotr Jaroszyński March 1, 2011

March 1, 2011

Hello, as my first real(silly) linux project I have implemented a block device that can expose the gpu ram available on nvidia cards while not interfering with normal gpu chores. That was achieved by a userspace daemon that uses cuda to manage the gpu ram and a linux kernel module to proxy the I/O requests to it. The longer story is at [1] and the code is at [2]. As I am pretty new to kernel hacking I would really appreciate you looking at the code and pointing out the problems. Apart from that I have a few specific questions: - Can the make_request function (set with blk_queue_make_request) be called from interrupt context? Should I be using spin_lock_irq in it? - see [3] - Is reading a pointer member variable of a struct atomic? - see [4] - Are there any safe ways for userspace and kernel to communicate when handling swapping? E.g. If the userspace is mlockall()ed, is calling a syscall that doesn't sleep safe? [1] - http://blog.piotrj.org/2011/03/cudaram-block-device-exposing-nvidia.html [2] - https://github.com/peper/cudaram [3] - https://github.com/peper/cudaram/blob/master/kmod/cudaram.c#L81 [4] - https://github.com/peper/cudaram/blob/master/kmod/cudaram.c#L420 -- Best Regards Piotr Jaroszyński

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To display indirect block numbers?
by kashish bhatia March 1, 2011

March 1, 2011

Hi all , If I want to display block numbers of a file. For instance file size is 64KB and block size is 4KB. So the data will accommodate in 16 blocks. Now I accessed an array named "i_block[ ]" present in ext2_inode structure. This array stores the block numbers of a file. The first 12 blocks are direct blocks which will store 48KB data of file and the 13th block will be single indirect block which will store the rest of the data. In this way I can directly get the data of 48KB by referring first 12 direct blocks. My question is how can I access this 13th block to get the remaining block numbers which will directly point to rest of the data. -- Regards, Kashish

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[PATCH 1/5] tg3: use <linux/io.h> and <linux/uaccess.h> instead <asm/io.h> and <asm/uaccess.h>
by Javier Martinez Canillas March 1, 2011

March 1, 2011

It is proper style to include linux/foo.h instead asm/foo.h if both exist Signed-off-by: Javier Martinez Canillas <martinez.javier(a)gmail.com> --- drivers/net/tg3.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index 6be4185..4410d73 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -48,9 +48,9 @@ #include <net/ip.h> #include <asm/system.h> -#include <asm/io.h> +#include <linux/io.h> #include <asm/byteorder.h> -#include <asm/uaccess.h> +#include <linux/uaccess.h> #ifdef CONFIG_SPARC #include <asm/idprom.h> -- 1.7.2.3

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interrupting the compile process and restart from where I stopped
by Tapas Mishra March 1, 2011

March 1, 2011

Hi, is there a way I can interrupt the ongoing kernel compile process and power off my machine and when I can get back to it then restart from where I had stopped the kernel compilation which I had interrupted.

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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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