From owner-freebsd-scsi Mon Mar 4 18: 2:56 2002 Delivered-To: freebsd-scsi@freebsd.org Received: from mail.mirapoint.com (mail.mirapoint.com [63.107.133.18]) by hub.freebsd.org (Postfix) with ESMTP id 859E837B400 for ; Mon, 4 Mar 2002 18:02:53 -0800 (PST) Received: from mail.mirapoint.com (localhost.mirapoint.com [127.0.0.1]) by mail.mirapoint.com (Mirapoint Messaging Server MOS 3.1.0.43) with SMTP id AOD05455 (AUTH cer); Mon, 4 Mar 2002 18:02:46 -0800 (PST) Message-Id: <200203050202.AOD05455@mail.mirapoint.com> Received: from 192.168.1.94 by mail.mirapoint.com (Mirapoint Messaging Server MOS 3.1.0.43) with HTTPS/1.1; Mon, 4 Mar 2002 18:03:22 -0800 Date: Mon, 4 Mar 2002 18:03:22 -0800 From: Carl Reisinger Subject: Writing > 64KB records to SCSI Tape, FreeBSD 4.1 (?) To: freebsd-scsi@FreeBSD.org Reply-To: cer@mirapoint.com X-Mailer: Mirapoint Webmail Direct 3.1.0.43 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org I would like to write records of 128KB to a SCSI tape device (DLT 7 or 8000, LTO). While MAXPHYS is 128KB, the code in kern_physio:physio will adjust the max size based on the value of dev->si_iosize_max. It my case it appears that this value is 0 (or < PAGE_SIZE), so physio will set si_iosize_max to DFLTPHYS which is defined to be 64KB. In any case DFLTPHYS is the limit I am hitting. This in turn will cause the 128KB write to be broken into two 64KB writes, which just doesn't work for me. The best solution, for me, would be a change to scsi_sa.c that will set si_iosize_max for the device. Can anyone help? NOTE: While most of the kernel is based on 4.1-STABLE, I believe the CAM subsystem and scsi_sa has been lifted from 4.3. (The behaviour is the same under 4.5) Thanks, Carl Reisinger To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message