Messages in this thread | | | From | Jacob Chen <> | Date | Thu, 8 Mar 2018 18:00:45 +0800 | Subject | Re: [PATCH v5 03/16] media: rkisp1: Add user space ABI definitions |
| |
Hi Hans,
2018-02-07 20:00 GMT+08:00 Hans Verkuil <hverkuil@xs4all.nl>: > On 12/29/17 08:52, Shunqian Zheng wrote: >> From: Jeffy Chen <jeffy.chen@rock-chips.com> >> >> Add the header for userspace > > General note: I saw four cases where this documentation referred to the > datasheet. Three comments on that: > > 1) You don't say which datasheet. > 2) I assume the datasheet is under NDA?
This datasheet can't be got by customers, even under NDA.
> 3) You do need to give enough information so a reasonable default can be > used. I mentioned in an earlier review that creating an initial params > struct that can be used as a templete would be helpful (or even > required), and that would be a good place to put such defaults. >
It don't need a default config For applcation writers, they can just init it with zero data, and only set value for the part they concerned.
As for ABI, i have checked there is no mismatches. Those structures is 32 bit aligned both in 64bit/32bit env, since there is no 64bit value. "__attribute__ ((packed))" can avoid mismatches happen when we add a 64bit value to those structures.
As robin said, enums and bools are not guaranteed to be consistent between different compiler, so it's a potential risk. I have replace bools with unsigned char and enums with unsigned int.
> Regards, > > Hans
| |