On Mon, Jan 10, 2022 at 08:05:52AM +1300, Paulo Miguel Almeida wrote: > On Sun, Jan 09, 2022 at 03:49:50PM +0000, Sidong Yang wrote: > > On Sun, Jan 09, 2022 at 11:26:52AM +1300, Paulo Miguel Almeida wrote: > > > > Hi, Paulo. > > Thanks for the patch. > > I have some opinion below. > > thanks for taking the time to review my patch :) > > > > this driver relies on exposing a char device to userspace to tx > > > messages. Every message can be sent using different trasmitter settings > > > such so the tx_cfg must be written before sending any messages. > > > Failing to do so will cause the message to fail silently depending on > > > printk/dynamic_debug settings which makes it hard to troubleshoot. > > > > > > This patch add a control variable that will get initialized once tx_cfg > > > is set for the fd used when interacting with the char device. > > > > I don't know that adding flag is good idea. It seems that initializing > > to default is better than this. > > the reasons why I thought that the flag was a good approach is because of > these points: > > 1 - it returns an error to userspace to help the developers > troubleshooting what is missing/required to make a message to be > successfully tx'ed. Unfortunately, once the message is in the chip > queue, there isn't much that the user can know so, from my humble point > of view, any way we can avoid hard-to-debug problems, we should. I understood that you mean that user has difficult to debug when it write message before initializing. If so, user would get debug message that some tx_cfg members are invalid. I think the point is which message would be useful for debugging. 'Some member is invalid' or 'tx_cfg is uninitialized'. I think the latter that you said is more accurate than before one. I think it make sense. > > 2 - rf69 work with multiple frequencies (315,433,868 and 915MHz) in which > acceptance varies from region to region. Essentially, picking 1 default > frequency may be ideal for one place but not right for another. Actually, I don't have idea about this. I want to know that how to other module like this handle this. Thanks, Sidong > > Let me know if you agree with my train of thought above and if not, > share with me your point of view. > > thanks, > > Paulo A. >
