> FD_ZERO(&sel);
> FD_SET(handle, &sel);
> ret = select(1, &sel, NULL, NULL, NULL);
I think, it should be ret = select(handle+1, &sel, NULL, NULL, NULL);
Otherwise your descriptor (handle) will not be polled on.
Regards
Mohanlal
----- Original Message -----
From: "Thorsten Kruse" <thokruse@xxxxxx>
To: <kernelnewbies@xxxxxxxxxxxx>
Sent: Wednesday, September 29, 2004 3:23 PM
Subject: Problem with select
> Hi!
>
> Currently I'm writing a char-driver for a serial multiportcard within
> my degree dissertation. The only thing that doesn´t work is the
> poll-routine. I have no idea what´s going wrong, I hope anyone can
> help me.
> The Problem is that the kernel never executes my poll-routine. This
> routine is registered in the struct file_operations in my driver. The
> poll-Routine looks like this:
>
> static unsigned int addi_poll(struct file *filp, poll_table *wait)
> {
> unsigned int mask = 0;
> addi_module *module_info;
>
> module_info = (addi_module *) filp->private_data;
> printk(KERN_INFO "Select\n");
> /*module_info->readq is the waitqueue*/
> poll_wait(filp, &module_info->readq, wait);
> mask |= (POLLIN | POLLRDNORM);
>
> return(mask);
> }
>
> Every time data is available my isr runs the following codeline:
>
> wake_up_interruptible(&module_info->readq);
>
> The source of my application contains the following lines:
> ...
> int handle;
> fd_set sel;
>
> handle = open("/dev/ttySA0", O_RDWR | O_NONBLOCK);
> if(handle < 0)
> {
> printf("Can`t find device\n");
> return(1);
> }
> FD_ZERO(&sel);
> FD_SET(handle, &sel);
> ret = select(1, &sel, NULL, NULL, NULL);
> ...
>
> When I´m running the application it will never leave the select,
> although data is incoming and wake_up_interruptible executes. Also the
> output of printk is never printed out, so it seems that my routine is
> never entered.
>
> Can anybody tell me what´s going wrong with that? For any hints I
> would be very thankful.
>
>
> Best regards
> Thorsten Kruse
>
>
> --
> GMX ProMail mit bestem Virenschutz http://www.gmx.net/de/go/mail
> +++ Empfehlung der Redaktion +++ Internet Professionell 10/04 +++
>
>
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
> Archive: http://mail.nl.linux.org/kernelnewbies/
> FAQ: http://kernelnewbies.org/faq/
>
>
--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
