Re: [PATCH] serial/uart: Add tunable RX interrupt trigger I/F of FIFO buffers

[Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>]

Hi Greg,

Thank you for your reply.

[snip]

>> diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
>> index 143dacb..d2e56a4 100644
>> --- a/include/uapi/asm-generic/ioctls.h
>> +++ b/include/uapi/asm-generic/ioctls.h
>> @@ -78,6 +78,8 @@
>>   #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
>>   #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
>>
>> +#define TIOCSFIFORTRIG	0x5441
>
> Please define this as a "proper" ioctl command by using the correct IO*
> macros.

OK. I'll use _IOW as follows:

#define TIOCSFIFORTRIG    _IOW('T', 0x41, unsigned char)

> Also, why pass a pointer to a variable, and not just the value itself?

Ah, it's no big reason.
It will pass just the value itself in V2.

> And are you sure there's no other way to do this already?  It's odd that
> no one else has ever hit this before...

According to a manual of setserial command, we could set RX interrupt
trigger only for the Hayes ESP serial driver. However, current kernel
does not support Hayes ESP serial[1]. I couldn't find this feature for
current 8250/16X50 drivers.

[1] https://lkml.org/lkml/2009/12/11/500

Thanks,
Yoshihiro YUNOMAE

-- 
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@hitachi.com