Re: [TTY] 2 points seems strange to me.

[Paul Fulghum]

Franck Bui-Huu wrote:
> Looking at TTY code, I noticed a weird test done in "opost_bock"
> located in n_tty.c file. I don't understand why the following test is
> done at the start of the function:
> if (nr > sizeof(buf))
>        nr = sizeof(buf);
> Actually it limits the size of processing blocks to 4 bytes and I can't
> find a reason why.

No, it limits the size to 80 bytes,
which is the size of buf.

sizeof returns the size of the char array buf[80]
(standard C)

> Second point, a lot of serial drivers call in their interrupt handler
> "tty_flip_buffer_push" function. This function must no be called
> in interrupt context. Why is it done anyway ?

Calling tty_flip_buffer_push() is fine from interrupt
as long as tty->low_latency is not set. It just queues
work for later.

--
Paul Fulghum
Microgate Systems, Ltd.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/