Userspace issue with DVB driver includes

Hello!

I think it was the change from asm/types.h to linux/types.h:

-#include <asm/types.h>
+#include <linux/types.h>

...which somehow broke the VDR build with recent DVB driver releases (see snippet A below).

The common workaround/solution to this seems to be to add a "-D__KERNEL_STRICT_NAMES".

But this feels wrong to me.

Reordering the includes and making sure <sys/*> is included before <linux/*> solves this issue too.

But ideally the include order shouldn't matter at all.

So my question is: How to deal with this? What's the recommended way for userspace applications to include linux/dvb headers?

Here's a small example, that fails to compile with 2.6.29:

// #include <sys/types.h>
// #define __KERNEL_STRICT_NAMES

#include <linux/dvb/frontend.h>
#include <linux/dvb/video.h>

int main()

{
    return 0;
}

Two workarounds to this problem are to define __KERNEL_STRICT_NAMES or including <sys/*> before the linux/dvb includes.

Any comments, suggestions?

Please see also:

http://www.linuxtv.org/pipermail/linux-dvb/2009-March/031934.html

bye,

Tobias

--- snippet A ---

In file included from /usr/include/netinet/in.h:24,

                 from /usr/include/arpa/inet.h:23,
                 from config.h:13,
                 from channels.h:13,
                 from device.h:13,
                 from dvbdevice.h:15,
                 from dvbdevice.c:10:

/usr/include/stdint.h:41: error: conflicting declaration 'typedef long int int64_t'
/usr/include/linux/types.h:98: error: 'int64_t' has a previous declaration as 'typedef __s64 int64_t'
/usr/include/stdint.h:56: error: conflicting declaration 'typedef long unsigned int uint64_t'
/usr/include/linux/types.h:96: error: 'uint64_t' has a previous declaration as 'typedef __u64 uint64_t'

Hi Tobi,

I suspect that this were the upstream change that affected your work, right?
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b852d36b86902abb272b0f2dd7a56dd2d17ea88c

There are two changesets that will likely fix this issue:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=85efde6f4e0de9577256c5f0030088d3fd4347c1
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=9adfbfb611307060db54691bc7e6d53fdc12312b

Could you please try to apply they on 2.6.29 and see if those will solve the issue? If so, then we should probably add those on 2.6.29.2.

Anyway, in order to keep v4l-dvb aligned with upstream, I'll backport the above changesets into the development tree.

Cheers,
Mauro

Hi Mauro,

Yes, at least I thought so.

I've applied both patches to 2.6.29.1, but the problem still remains.

It's hard to figure out, who to blame for this.

Tobias

If you're compiling with a new kernel, you'll be expected to have installed the new kernel headers at /usr/include/linux. This is done by using "make headers_install" at the kernel tree.

Could you please try to do make headers_install and see if the problem persists? If the problem will still persist, then the better procedure is to open a bugzilla at bugzilla.kernel.org, and post an email about this at LKML, keeping LMML c/c, for us to follow the discussions.

Cheers,
Mauro

The root of the problem seems to be a clash between linux/types.h which defines some POSIX types also defined in glibc's stdint.h. I'm not sure, who to blame for this glibc or the kernel...
The problem seems not to be restricted to the DVB drivers, so this is probably the wrong list, but any comments are welcome!

Tobias

Of course I've installed the kernel headers. After all these headers are causing the trouble.

The change from asm/types.h to linux/types.h causes some POSIX types beeing declared, which are also defined in glibc's stdint.h.

As soon as I've decided whether it is a glibc or kernel issue, I'll do so.

Thanks for your help!

Tobias

Just for the record: Arnd Bergmann already prepared a patch for this, which unfortunately didn't made it into 2.6.29. The changesets you suggested were from Arnd Bergmann's patchset, but I think at least these changes would be required too:

http://git.kernel.org/?p=linux/kernel/git/jaswinder/linux-2.6-tip.git;a=commit;h=3a471cbc081b6bf2b58a48db13d734ecd3b0d437

(haven't tested it yet with just those three changesets)

See:

http://lkml.indiana.edu/hypermail/linux/kernel/0902.3/index.html#00955
http://git.kernel.org/?p=linux/kernel/git/jaswinder/linux-2.6-tip.git;a=shortlog;h=core/header-fixes

I've just applied the whole patchset from the core/header-fixes branch and
it works fine.

(Thx to Anssi Hannula for pointing me into the right direction:
http://lkml.indiana.edu/hypermail/linux/kernel/0902.3/00411.html)

Tobias