linux-imx

/* SPDX-License-Identifier: GPL-2.0 */

/*

   The compile-time configurable defaults for the Linux SCSI tape driver.

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   Copyright 1995-2003 Kai Makisara.

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   Last modified: Thu Feb 21 21:47:07 2008 by kai.makisara

*/

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#ifndef _ST_OPTIONS_H

#define _ST_OPTIONS_H

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/* If TRY_DIRECT_IO is non-zero, the driver tries to transfer data directly

   between the user buffer and tape drive. If this is not possible, driver

   buffer is used. If TRY_DIRECT_IO is zero, driver buffer is always used. */

#define TRY_DIRECT_IO 1

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/* The driver does not wait for some operations to finish before returning

   to the user program if ST_NOWAIT is non-zero. This helps if the SCSI

   adapter does not support multiple outstanding commands. However, the user

   should not give a new tape command before the previous one has finished. */

#define ST_NOWAIT 0

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/* If ST_IN_FILE_POS is nonzero, the driver positions the tape after the

   record been read by the user program even if the tape has moved further

   because of buffered reads. Should be set to zero to support also drives

   that can't space backwards over records. NOTE: The tape will be

   spaced backwards over an "accidentally" crossed filemark in any case. */

#define ST_IN_FILE_POS 0

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/* If ST_RECOVERED_WRITE_FATAL is non-zero, recovered errors while writing

   are considered "hard errors". */

#define ST_RECOVERED_WRITE_FATAL 0

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/* The "guess" for the block size for devices that don't support MODE

   SENSE. */

#define ST_DEFAULT_BLOCK 0

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/* The minimum tape driver buffer size in kilobytes in fixed block mode.

   Must be non-zero. */

#define ST_FIXED_BUFFER_BLOCKS 32

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/* Maximum number of scatter/gather segments */

#define ST_MAX_SG      256

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/* The number of scatter/gather segments to allocate at first try (must be

   smaller or equal to the maximum). */

#define ST_FIRST_SG    8

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/* The size of the first scatter/gather segments (determines the maximum block

   size for SCSI adapters not supporting scatter/gather). The default is set

   to try to allocate the buffer as one chunk. */

#define ST_FIRST_ORDER  5

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/* The following lines define defaults for properties that can be set

   separately for each drive using the MTSTOPTIONS ioctl. */

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/* If ST_TWO_FM is non-zero, the driver writes two filemarks after a

   file being written. Some drives can't handle two filemarks at the

   end of data. */

#define ST_TWO_FM 0

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