Re: [PATCH 5/5] tty: serial: uartlite: Prevent changing fixed parameters

[Maarten Brock <m.brock@vanmierlo.com>]

On 2021-07-30 07:25, Greg Kroah-Hartman wrote:
> On Thu, Jul 29, 2021 at 11:43:08AM -0400, Sean Anderson wrote:
>> 
>> 
>> On 7/29/21 11:32 AM, Greg Kroah-Hartman wrote:
>> > On Thu, Jul 29, 2021 at 11:26:59AM -0400, Sean Anderson wrote:
>> >>
>> >>
>> >> On 7/29/21 11:01 AM, Greg Kroah-Hartman wrote:
>> >> > On Fri, Jul 23, 2021 at 06:31:51PM -0400, Sean Anderson wrote:
>> >> > Through all of this, you are warning that nothing is supported, yet you
>> >> > are continuing on as if all of this worked just fine.
>> >>
>> >> We don't. The idea is that we see if (e.g.) CSIZE is something the
>> >> hardware can't produce, warn about it (once), and then set it to what we
>> >> can support.
>> >
>> > So you are ignoring what the user wanted, and doing whatever you wanted.
>> >
>> > As you can only support one setting, why even care?  Just set it to what
>> > you want and ignore userspace's requests.
>> 
>> That is exactly what we are doing. We set it to what we can support 
>> and
>> ignore what userspace requested.
> 
> If you can only support one set of options, just set it and always fail
> the tcsetattr call which will allow userspace to know it shouldn't have
> tried to do that.

I have to disagree strongly here against *always*. If the user calls 
tcsetattr
to set it to exactly what is supported it *should not fail*. Every 
decent
(terminal) program will start by setting or getting the initial 
settings.

Maarten