Hi Chetan, On Tue, Dec 27, 2011 at 3:39 AM, Chetan Nanda <chetannanda@gmail.com> wrote:
Hi All,
I am facing a strange issue with the ioctl commands, and not able to find what wrong I am doing. I am trying with a dummy kernel driver and implemented ioctl command as follow:
in my_ioctl.h #define READHWREG_MAGIC_NUMBER 0x15 #define READHWREG_CAM_READPE _IOR(READHWREG_MAGIC_NUMBER, 1, int*)
But the value of 'READHWREG_CAM_READPE' is comes out to be different in userspace (in the application) and kernel space (in the driver).
In userspace I used ioctl as ... printf("\ncommand %x \n",READHWREG_CAM_READPE); <-- command 80041501 error = ioctl(g_DevFileId, READHWREG_CAM_READPE); ..
In kernel space
int readHwReg_ioctl(struct inode *node, struct file *filp, unsigned int cmd, unsigned long arg) { ... printk("\n%d %s cmd = %x\n",__LINE__,__FUNCTION__,cmd); <--- cmd = bee6a9d4
Back in 2.6.36, the ioctl member of the struct file_operations structure (which took 4 arguments) was finally deprecated, replaced with unlocked_ioctl (which only takes 3 arguments). If you just renamed and ignored the compiler warnings, then that explains your problem. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com