When appl_ptr is updated let low-level driver know, e.g. to let the low-level driver/hardware pre-fetch data opportunistically.
The existing .ack callback could be used but it would need to be extended with new arguments, resulting in multiple changes in legacy code.
I wouldn't mind changing these callers. They aren't so many, after all.
Yes this was one of the discussions we had in the past. I don't recall the conclusion so had recommened to keep as is and discuss here.
Do you think it's better to do that or use a new one :)
It's OK to change ack callback, and actually it'll be cleaner. But then it'll be a problem in the next patch, I suppose :)
The main problem is test/coverage of legacy v. alignment of functionality. If we change .ack() then others will have to test for the changes and there's a risk of a regression on a specific platform that wasn't tested - Murphy's law applies.