Re: Devices.

[Johnny Billquist <bqt%softjar.se@localhost>]

On 2021-05-29 22:26, David Holland wrote:
> There are a number of infelicities in the way we currently handle the
> I/O plumbing for devices in the kernel. These include:

[...]

Just looking/thinking about the ioctl part - you say abolish it inside 
the kernel. So does that mean that we keep the ioctl() interface for 
user programs, but we'd create a system function that will translate 
ioctl() calls from user programs to different function calls based on 
class and function.

Which means any time anyone wants to add some new kind of function to a 
device, you'd have to adjust the ioctl() system call, the class, all 
devices of that class, and of course your specific driver which you want 
to do something with the hardware.

Or did I misunderstand something here?

I'm not trying to shoot anything down at this time. Just trying to 
understand the implications of the suggestion.

I sortof like the idea of getting some generalization, which classes 
would bring. But the problem with ioctl causing duplication and all kind 
of efforts is at the same time also a strength in that you can add 
something new to a device without having to care at all about all other 
devices and code. Since nothing else really tries to understand ioctls. 
Flexible, but more effort if you want coherent behavior.

  Johnny

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
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