Small fixes: use /dev instead of /tmp for mailbox, fixed unmapmem() to avoid exit(-1) at ws2811_fini, use 249 as device major to avoid crash on Kernel >=4.1

[plan44]

No description provided.

[Gadgetoid]

I've started getting reports of issues with this library and permissions errors/missing devices in /tmp, is this fix somewhat related? I'm going to give it a try in our Unicorn HAT library either way.

[tejonbiker]

I have the same behavior, seems like the program can create the /tmp/mailbox-XXXX but can't open it. I added this code to the mbox_open() function in mailbox.c:

if (file_desc < 0) {
sprintf(system_qry,"file %s",filename);
system(system_qry);
printf("Can't open device file %s: %m\n", filename);
unlink(filename);
return -1;
}

And return this:

/tmp/mailbox-3725: character special
Can't open device file /tmp/mailbox-3725: No such device or address.

[tejonbiker]

Sorry, I forgot mention my kernel info:

uname -a
Linux raspberrypi 4.1.6-v7+ #810 SMP PREEMPT Tue Aug 18 15:32:12 BST 2015 armv7l GNU/Linux

[plan44]

@Gadgetoid yes, this fix is related. The regular tmpfs (ram disk file system) cannot have character device nodes, so if /tmp is mapped to a tmpfs (as it is on minibian, a stripped down flavor of the Raspian distribution) the original library does not work.
However, /dev seems always located on a special flavor of tmpfs called devtmpfs which can have character device nodes, so it works for the mailbox.

[Gadgetoid]

Looks like this fix is related to the Minibian issue, but not to the new one that has developed as of Kernel 4.1.6 which is what @tejonbiker is referring to. I've updated the firmware on a Pi and confirmed the problem- since there's no way of raising issues against this repository, and it's off-topic for this PR, I've raised a new one upstream for discussion: jgarff#41

[ghost]

Take a look at this, with the changes from the link rpi_ws281x works fine for me.