Re: [PATCH v2 7/9] [media] v4l2: introduce v4l2_timeval

On Friday 18 September 2015 11:52:28 Hans Verkuil wrote:

On 09/18/15 11:43, Arnd Bergmann wrote:

quoted

On Friday 18 September 2015 11:27:40 Hans Verkuil wrote:

quoted

Ah, OK. Got it.

I think this is dependent on the upcoming media workshop next month. If we
decide to redesign v4l2_buffer anyway, then we can avoid timeval completely.
And the only place where we would need to convert it in the compat code
hidden in the v4l2 core (likely v4l2-ioctl.c).

Ah, I think I understood the idea now, I missed that earlier when you mention
the idea.

So what you are saying here is that you could come up with a new unambiguous
(using only __u32 and __u64 types and no pointers) format that gets exposed
to a new set of ioctls, and then change the handling of the existing three
formats (native 64-bit, traditional 32-bit, and 32-bit with 64-bit time_t)
so they get converted into the new format by the common ioctl handling code?

Right. Drivers only see the new struct, and only v4l2-ioctl.c (and possible
v4l2-compat-ioctl32.c) see the old ones.

BTW, I will probably pick up patches 4 and 6 for 4.4. That should help a bit.

Ok, thanks!

I guess it's up to Mauro to pick up the first three patches?

As I don't see anything more to do for me here until you've had the
discussion about the new format, I'll move on to another subsystem now.
I have around 70 patches waiting to be submitted, plus the system call
series.

	Arnd