I really really appreciate your help.
That is a very stupid bug, I should review my code more carefully before I
sent out for help. Sorry about that, I guess somehow my brain just messed
Anyway, I did turn on the CONFIG_PROC_FS.
I also mount the usb by "mount -t usbdevfs none /proc/bus/usb"; and if I
"cat /proc/filesystems" it does show "usbdevfs".
However, is there a "inputdevfs" and is there a similar command line such as
"mount -t inputdevfs none /proc/bus/input"?
I don't see anything like "CONFIG_INPUT_DEVICEFS"?
I am using 2.4.18 kernel.
From: Jan-Benedict Glaw [mailto:firstname.lastname@example.org]
Sent: Thursday, April 15, 2004 2:22 PM
To: Linux/MIPS Development
Subject: Re: questions about keyboard
On Thu, 2004-04-15 14:08:54 -0600, Xu, Jiang <Jiang.Xu@echostar.com> wrote
in message <F71A246055866844B66AFEB10654E7860F1B10@riv-exchb6.echostar.com>:
> Thanks for the reply, I did some testing and found some interesting
> 1. Everytime I push the key on the keyboard, I can see something out
> from /dev/input/event0 by "cat /dev/input/event0". However, I don't
> see a directory named "proc/input", did I miss configure something in
> the kernel?
Maybe your kernel isn't configured with CONFIG_PROC_FS=y ? Maybe it's not
> 2. read() does work and is a blocking read. However, if I use
> select, then it does not work.
> Select() never detects the state change.
> Here is the sample code I am using:
> int test_fd = -1;
No need to initialize - you're assigning a value before accessing it.
> fd_set rfds;
> struct timeval tv;
> tv.tv_sec = 1;
> tv.tv_usec = 0;
tv_* need to be set before *every* select () invocation, not only once.
> test_fd = open("/dev/input/event0", O_RDONLY);
> if( test_fd < 0 )
> while( 1 )
> FD_SET(test_fd, &rfds);
> retval = select( 1, &rfds, NULL, NULL, &tv );
That's wrong. The "1" should be "fd + 1".
> if( retval )
> printf("\nDetects something....");
A negative retval would also be != 0 ...
> What could be wrong?
Most probably it's the hardcoded "1" with the select. That is, select only
looks at all fd's which are smaller than one, so only fd=0 would be testes,
but this one isn't in the set, so...
Jan-Benedict Glaw email@example.com . +49-172-7608481
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