Message-ID: <42160290.3070000@microgate.com>
Date: Fri, 18 Feb 2005 08:58:24 -0600
From: Paul Fulghum <paulkf@microgate.com>
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To: franck.bui-huu@innova-card.com
CC: linux-kernel@vger.kernel.org
Subject: Re: [TTY] 2 points seems strange to me.
References: <20050217175150.D8E015B874@frankbuss.de> <20050217181241.A22752@flint.arm.linux.org.uk> <4215B5AC.4050600@innova-card.com>
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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.
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