From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id ED35B67B89 for ; Wed, 6 Sep 2006 10:45:40 +1000 (EST) Subject: Re: On the transfer of data from the uart.c driver to the tty layer... From: Benjamin Herrenschmidt To: Alejandro C In-Reply-To: References: Content-Type: text/plain Date: Wed, 06 Sep 2006 10:45:26 +1000 Message-Id: <1157503526.22705.153.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2006-09-05 at 14:56 +0000, Alejandro C wrote: > Hi all, > > I'm working on a the uart.c driver to add support for SCCs in HDLC mode. The > application I'm going to run on top will be sending Ethernet packets > encapsulated in the data field of an HDLC frame. The idea was to make the > buffer big enough so that a whole Eth. packet (max 1518 octects) could fit > in just one buffer. I let the CPM interrupt on a frame basis and the problem > I've come across is that the receive buffer in the struct tty_struct, where > the tty layer collects the data from the driver > (tty_struct.tty_flip_buffer.char_buf), is only 1024 bytes > (2*TTY_FLIPBUF_SIZE). The easiest at this stage would be to make those > buffers larger, but I don't know what sort of impact this might have... Any > tips? > Any ideas on how to solve it in another fashion? > > Help will be highly appreciated. You should ask on the linux-kernel mailing list, possibly CC'ing Alan Cox who seem to have put his hands a lot in the TTY code lately. Ben.