The code in parallel port driver, your program is invoking can be seen at following link: http://lxr.linux.no/source/drivers/char/ppdev.c?v=2.4.21#L342 The error string ("ppdev0: no associated port") is printed in register_device() function. This function can be seen at: http://lxr.linux.no/source/drivers/char/ppdev.c?v=2.4.21#L286 In this function when we call parport_find_number() function, it returns NULL value, due to which the error string is printed. Try to find out the problem in parport_find_number() function, which you can find at following link: http://lxr.linux.no/source/drivers/parport/share.c?v=2.4.21#L826 Hope it helps. Regards, Gaurav -----Original Message----- From: kernelnewbies-bounce@xxxxxxxxxxxx [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of amith Sent: Tuesday, July 27, 2004 11:28 AM To: kernel Subject: user space - printer driver ? hi all, i tried the following code on my computer. i tried it from a tutorial on the net. It explains the Linux-2.4 parallel port subsystem. #include<linux/ppdev.h> #include<sys/types.h> #include<sys/ioctl.h> ..... #define DEVICE_FILE "/dev/parport0" main() { int p_fd; p_fd = open(DEVICE_FILE,O_RDWR); if(p_fd < 0) { perror(" in open "); exit(0); } if( ioctl(p_fd, PPCLAIM)) { perror("in ioctl"); exit(0); } } i'am planning to write a driver for it, so i decided to first understand the Parport subsystem on Linux-2.4. Now, ioctl() fails and perror reports : in ioctl : no such device or address. i get a message in /var/log/messages saying : ppdev0: no associated port. could someone explain why this could happen and how i could get out of this ? cheers, Amith PS: i tried with parport0, parport1,parport2 - device files , without any change in errors :-( ! tried to print documents on my printer from Windows applications like MS-Word, just to check whether the parallel port is working and iam able to print . -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
