On 11/26/19 4:17 PM, Arnd Bergmann wrote:
On Tue, Nov 26, 2019 at 3:15 PM Hans Verkuil hverkuil@xs4all.nl wrote:
Then use that in the struct v4l2_buffer definition:
struct v4l2_buffer { ... #ifdef __KERNEL__ struct __kernel_v4l2_timeval timestamp; #else struct timeval timestamp; #endif
That keeps struct v4l2_buffer fairly clean. And it also makes it possible to have a bit more extensive documentation for the struct __kernel_v4l2_timeval without polluting the actual struct v4l2_buffer definition.
Yes, good idea. I've added this version now:
#ifdef __KERNEL__ /*
- This corresponds to the user space version of timeval
- for 64-bit time_t. sparc64 is different from everyone
- else, using the microseconds in the wrong half of the
- second 64-bit word.
*/ struct __kernel_v4l2_timeval { long long tv_sec; #if defined(__sparc__) && defined(__arch64__) int tv_usec; int __pad; #else long long tv_usec; #endif }; #endif
I briefly considered using #else #define __kernel_v4l2_timeval timeval to avoid the second #ifdef, but went back to your version again for clarify.
The videodev2.h header is something users of the API look at a lot and having this really ugly kernel timestamp in there is not acceptably IMHO. But splitting it off should work.
Do you also mean moving it into a separate header file, or just outside of struct v4l2_buffer? Since it's hidden in #ifdef __KERNEL__, it could be moved to media/ioctl.h or elsewhere.
I've thought about that, but that risks having to change drivers since they would now have to include another header to get the right timeval definition. In the end I don't think it is worth the effort.
I think it is best to define __kernel_v4l2_timeval just before the struct v4l2_requestbuffers definition rather than before the struct v4l2_buffer. That way it doesn't interfere with the userspace structs for the buffer API.
Regards,
Hans
Arnd