patch-2.1.66 linux/drivers/char/ftape/fdc-isr.c

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diff -u --recursive --new-file v2.1.65/linux/drivers/char/ftape/fdc-isr.c linux/drivers/char/ftape/fdc-isr.c
@@ -1,813 +0,0 @@
-/*
- *      Copyright (C) 1994-1995 Bas Laarhoven.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; see the file COPYING.  If not, write to
- the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
-
- $Source: /home/bas/distr/ftape-2.03b/RCS/fdc-isr.c,v $
- $Author: bas $
- *
- $Revision: 1.36 $
- $Date: 1995/05/27 08:54:21 $
- $State: Beta $
- *
- *      This file contains the interrupt service routine and associated
- *      code for the QIC-40/80 tape streamer device driver.
- */
-
-#include <linux/ftape.h>
-#include <asm/io.h>
-#include <asm/dma.h>
-
-#define volatile		/* */
-
-#include "tracing.h"
-#include "fdc-isr.h"
-#include "qic117.h"
-#include "fdc-io.h"
-#include "ftape-ctl.h"
-#include "ftape-rw.h"
-#include "ftape-io.h"
-#include "calibr.h"
-#include "ftape-bsm.h"
-
-/*      Global vars.
- */
-volatile int expected_stray_interrupts = 0;
-volatile int seek_completed = 0;
-volatile int interrupt_seen = 0;
-volatile int expect_stray_interrupt = 0;
-int random_rw = 0;
-
-/*      Local vars.
- */
-typedef enum {
-	no_error = 0, id_am_error = 0x01, id_crc_error = 0x02,
-	data_am_error = 0x04, data_crc_error = 0x08,
-	no_data_error = 0x10, overrun_error = 0x20,
-} error_cause;
-static int hide_interrupt;
-static int stop_read_ahead = 0;
-
-
-static void print_error_cause(int cause)
-{
-	TRACE_FUN(8, "print_error_cause");
-
-	switch (cause) {
-	case no_data_error:
-		TRACE(4, "no data error");
-		break;
-	case id_am_error:
-		TRACE(4, "id am error");
-		break;
-	case id_crc_error:
-		TRACE(4, "id crc error");
-		break;
-	case data_am_error:
-		TRACE(4, "data am error");
-		break;
-	case data_crc_error:
-		TRACE(4, "data crc error");
-		break;
-	case overrun_error:
-		TRACE(4, "overrun error");
-		break;
-	default:
-	}
-	TRACE_EXIT;
-}
-
-static char *
-get_fdc_mode_text(fdc_mode_enum fdc_mode)
-{
-	switch (fdc_mode) {
-	case fdc_idle:
-		return "fdc_idle";
-	case fdc_reading_data:
-		return "fdc_reading_data";
-	case fdc_seeking:
-		return "fdc_seeking";
-	case fdc_writing_data:
-		return "fdc_writing_data";
-	case fdc_reading_id:
-		return "fdc_reading_id";
-	case fdc_recalibrating:
-		return "fdc_recalibrating";
-	default:
-		return "unknown";
-	}
-}
-
-static void
-decode_irq_cause(fdc_mode_enum fdc_mode, byte st[],
-		 char **fdc_mode_txt, error_cause * cause)
-{
-	TRACE_FUN(8, "decode_irq_cause");
-
-	/*  Valid st[], decode cause of interrupt.
-	 */
-	*fdc_mode_txt = get_fdc_mode_text(fdc_mode);
-	switch (st[0] & ST0_INT_MASK) {
-	case FDC_INT_NORMAL:
-		TRACEx1(fdc_mode == fdc_reading_id ? 6 : 5,
-			"normal completion: %s", *fdc_mode_txt);
-		*cause = no_error;
-		break;
-	case FDC_INT_ABNORMAL:
-		TRACEx1(5, "abnormal completion %s", *fdc_mode_txt);
-		TRACEx3(6, "ST0: 0x%02x, ST1: 0x%02x, ST2: 0x%02x",
-			st[0], st[1], st[2]);
-		TRACEx4(6, "C: 0x%02x, H: 0x%02x, R: 0x%02x, N: 0x%02x",
-			st[3], st[4], st[5], st[6]);
-		if (st[1] & 0x01) {
-			if (st[2] & 0x01) {
-				*cause = data_am_error;
-			} else {
-				*cause = id_am_error;
-			}
-		} else if (st[1] & 0x20) {
-			if (st[2] & 0x20) {
-				*cause = data_crc_error;
-			} else {
-				*cause = id_crc_error;
-			}
-		} else if (st[1] & 0x04) {
-			*cause = no_data_error;
-		} else if (st[1] & 0x10) {
-			*cause = overrun_error;
-		}
-		print_error_cause(*cause);
-		break;
-	case FDC_INT_INVALID:
-		TRACEx1(5, "invalid completion %s", *fdc_mode_txt);
-		*cause = no_error;
-		break;
-	case FDC_INT_READYCH:
-		TRACEx1(5, "ready change %s", *fdc_mode_txt);
-		*cause = no_error;
-		break;
-	default:
-	}
-	TRACE_EXIT;
-}
-
-static void update_history(error_cause cause)
-{
-	switch (cause) {
-	case id_am_error:
-		history.id_am_errors++;
-		break;
-	case id_crc_error:
-		history.id_crc_errors++;
-		break;
-	case data_am_error:
-		history.data_am_errors++;
-		break;
-	case data_crc_error:
-		history.data_crc_errors++;
-		break;
-	case overrun_error:
-		history.overrun_errors++;
-		break;
-	case no_data_error:
-		history.no_data_errors++;
-		break;
-	default:
-	}
-}
-
-static void skip_bad_sector(buffer_struct * buff)
-{
-	TRACE_FUN(8, "skip_bad_sector");
-
-	/* Mark sector as soft error and skip it
-	 */
-	if (buff->remaining > 0) {
-		++buff->sector_offset;
-		++buff->data_offset;
-		--buff->remaining;
-		buff->ptr += SECTOR_SIZE;
-		buff->bad_sector_map >>= 1;
-	} else {
-		++buff->sector_offset;	/* hack for error maps */
-		TRACE(1, "skipping last sector in segment");
-	}
-	TRACE_EXIT;
-}
-
-static void update_error_maps(buffer_struct * buff, unsigned error_offset)
-{
-	TRACE_FUN(8, "update_error_maps");
-	int hard = 0;
-
-	/* error_offset is a sector offset !
-	 */
-	if (buff->retry < SOFT_RETRIES) {
-		buff->soft_error_map |= (1 << error_offset);
-	} else {
-		buff->hard_error_map |= (1 << error_offset);
-		buff->soft_error_map &= ~buff->hard_error_map;
-		buff->retry = -1;	/* will be set to 0 in setup_segment */
-		hard = 1;
-	}
-	TRACEx2(4, "sector %d : %s error", SECTOR(error_offset),
-		hard ? "hard" : "soft");
-	TRACEx2(5, "hard map: 0x%08lx, soft map: 0x%08lx",
-		buff->hard_error_map, buff->soft_error_map);
-	TRACE_EXIT;
-}
-
-/*
- *  Error cause:   Amount xferred:  Action:
- *
- *  id_am_error         0           mark bad and skip
- *  id_crc_error        0           mark bad and skip
- *  data_am_error       0           mark bad and skip
- *  data_crc_error    % 1024        mark bad and skip
- *  no_data_error       0           retry on write
- *                                  mark bad and skip on read
- *  overrun_error  [ 0..all-1 ]     mark bad and skip
- *  no_error           all          continue
- */
-static void determine_progress(buffer_struct * buff, error_cause cause, int mode)
-{
-	TRACE_FUN(8, "determine_progress");
-	unsigned nr_not_xferred;
-	unsigned nr_xferred;
-	unsigned dma_residue;
-
-	/*  Using less preferred order of disable_dma and get_dma_residue
-	 *  because this seems to fail on at least one system if reversed!
-	 */
-	dma_residue = get_dma_residue(fdc.dma);
-	disable_dma(fdc.dma);
-	nr_xferred = buff->sector_count * SECTOR_SIZE - dma_residue;
-	if (cause == no_error && dma_residue == 0) {
-		nr_not_xferred = 0;
-	} else {
-		if (cause == no_error) {
-			TRACEx1(4, "unexpected DMA residue: 0x%04x", dma_residue);
-		} else {
-			TRACEx1(6, "DMA residue = 0x%04x", dma_residue);
-		}
-		nr_not_xferred = ((dma_residue + (SECTOR_SIZE - 1)) / SECTOR_SIZE);
-		buff->sector_count -= nr_not_xferred;	/* adjust to actual value */
-	}
-	/*  Update var's influenced by the DMA operation.
-	 */
-	if (buff->sector_count > 0) {
-		buff->sector_offset += buff->sector_count;
-		buff->data_offset += buff->sector_count;
-		buff->ptr += buff->sector_count * SECTOR_SIZE;
-		buff->remaining -= buff->sector_count;
-		buff->bad_sector_map >>= buff->sector_count;
-	}
-	if (cause == no_error) {
-		TRACEx1(5, "%d Sector(s) transferred", buff->sector_count);
-	} else if (cause == no_data_error) {
-		TRACEx1(5, "Sector %d not found", SECTOR(buff->sector_offset));
-	} else if (nr_xferred > 0 || cause == id_crc_error ||
-		   cause == id_am_error || cause == data_am_error) {
-		TRACEx1(5, "Error in sector %d", SECTOR(buff->sector_offset));
-	} else if (cause == overrun_error) {
-		/* got an overrun error on the first byte, must be a hardware problem
-		 */
-		TRACE(-1, "Unexpected error: failing DMA controller ?");
-	} else {
-		TRACEx1(4, "Unexpected error at sector %d", SECTOR(buff->sector_offset));
-	}
-	/*  Sector_offset points to the problem area, except if we got
-	 *  a data_crc_error. In that case it points one past the failing
-	 *  sector.
-	 *  Now adjust sector_offset so it always points one past he
-	 *  failing sector. I.e. skip the bad sector.
-	 */
-	if (cause != no_error) {
-		if (cause != data_crc_error) {
-			skip_bad_sector(buff);
-		}
-		update_error_maps(buff, buff->sector_offset - 1);
-	}
-	TRACE_EXIT;
-}
-
-static int calc_steps(int cmd)
-{
-	if (current_cylinder > cmd) {
-		return current_cylinder - cmd;
-	} else {
-		return current_cylinder + cmd;
-	}
-}
-
-static void pause_tape(unsigned segment, int retry, int fdc_mode)
-{
-	TRACE_FUN(8, "pause_tape");
-	int result;
-	/*  The 3rd initializer needs to be explicit or else gcc will
-	 *  generate a reference to memset :-(
-	 */
-	byte out[3] =
-	{FDC_SEEK, FTAPE_UNIT, 0};
-
-	/*  We'll use a raw seek command to get the tape to rewind
-	 *  and stop for a retry.
-	 */
-	++history.rewinds;
-	if (qic117_cmds[current_command].non_intr) {
-		TRACE(2, "motion command may be issued too soon");
-	}
-	if (retry && (fdc_mode == fdc_reading_data || fdc_mode == fdc_reading_id)) {
-		current_command = QIC_MICRO_STEP_PAUSE;
-		might_be_off_track = 1;
-	} else {
-		current_command = QIC_PAUSE;
-	}
-	out[2] = calc_steps(current_command);
-	result = fdc_command(out, 3);	/* issue QIC_117 command */
-	if (result < 0) {
-		TRACEx1(4, "qic-pause failed, status = %d", result);
-	} else {
-		location.known = 0;
-		runner_status = idle;
-		hide_interrupt = 1;
-		tape_running = 0;
-	}
-	TRACE_EXIT;
-}
-
-static void stop_tape(unsigned segment)
-{
-	TRACE_FUN(8, "stop_tape");
-	int result;
-	byte out[3] =
-	{FDC_SEEK, FTAPE_UNIT, calc_steps(QIC_STOP_TAPE)};
-
-	if (qic117_cmds[current_command].non_intr) {
-		TRACE(2, "motion command may be issued too soon");
-	}
-	current_command = QIC_STOP_TAPE;
-	/*  We'll use a raw seek command to get the tape to stop
-	 */
-	result = fdc_command(out, 3);	/* issue QIC_117 command */
-	if (result < 0) {
-		TRACEx1(4, "qic-stop failed, status = %d", result);
-	} else {
-		runner_status = idle;
-		hide_interrupt = 1;
-		tape_running = 0;
-	}
-	TRACE_EXIT;
-}
-
-static void continue_xfer(buffer_struct ** p_buff, error_cause cause,
-			  int fdc_mode, unsigned skip)
-{
-	TRACE_FUN(8, "continue_xfer");
-	buffer_struct *buff = *p_buff;
-	int write = (fdc_mode == fdc_writing_data);
-	byte fdc_op = (write) ? FDC_WRITE : FDC_READ;
-
-	if (skip > 0) {
-		/* This part can be removed if it never happens
-		 */
-		if (runner_status != running ||
-		    (buff->status != (write ? writing : reading))) {
-			TRACEx2(1, "unexpected runner/buffer state %d/%d",
-				runner_status, buff->status);
-			buff->status = error;
-			*p_buff = next_buffer(&head);	/* finish this buffer */
-			runner_status = aborting;
-			fdc_mode = fdc_idle;
-		}
-	}
-	if (buff->remaining > 0 && calc_next_cluster(&buffer[head]) > 0) {
-		/* still sectors left in current segment, continue with this segment
-		 */
-		if (setup_fdc_and_dma(&buffer[head], fdc_op) < 0) {
-			/* failed, abort operation
-			 */
-			buff->bytes = buff->ptr - buff->address;
-			buff->status = error;
-			buff = *p_buff = next_buffer(&head);	/* finish this buffer */
-			runner_status = aborting;
-			fdc_mode = fdc_idle;
-		}
-	} else {
-		/* current segment completed
-		 */
-		unsigned last_segment = buff->segment_id;
-		int eot = ((last_segment + 1) % segments_per_track) == 0;
-		int next = buff->next_segment;	/* 0 means stop ! */
-
-		buff->bytes = buff->ptr - buff->address;
-		buff->status = done;
-		buff = *p_buff = next_buffer(&head);
-		if (eot) {
-			/* finished last segment on current track, can't continue
-			 */
-			runner_status = logical_eot;
-			fdc_mode = fdc_idle;
-		} else if (next > 0) {
-			/* continue with next segment
-			 */
-			if (buff->status == waiting) {
-				if (write && next != buff->segment_id) {
-					TRACE(5, "segments out of order, aborting write");
-					runner_status = do_abort;
-					fdc_mode = fdc_idle;
-				} else {
-					setup_new_segment(&buffer[head], next, 0);
-					if (stop_read_ahead) {
-						buff->next_segment = 0;
-						stop_read_ahead = 0;
-					}
-					if (calc_next_cluster(&buffer[head]) == 0 ||
-					    setup_fdc_and_dma(&buffer[head], fdc_op) != 0) {
-						TRACEx1(1, "couldn't start %s-ahead", (write) ? "write" : "read");
-						runner_status = do_abort;
-						fdc_mode = fdc_idle;
-					} else {
-						buff->status = (write) ? writing : reading;	/* keep on going */
-					}
-				}
-			} else {
-				TRACEx1(5, "all input buffers %s, pausing tape",
-					(write) ? "empty" : "full");
-				pause_tape(last_segment, 0, fdc_mode);
-				runner_status = idle;	/* not quite true until next irq */
-			}
-		} else {
-			/* don't continue with next segment
-			 */
-			TRACEx1(5, "no %s allowed, stopping tape",
-				(write) ? "write next" : "read ahead");
-			if (random_rw) {
-				stop_tape(last_segment);
-			} else {
-				pause_tape(last_segment, 0, fdc_mode);
-			}
-			runner_status = idle;	/* not quite true until next irq */
-		}
-	}
-	TRACE_EXIT;
-	return;
-}
-
-static void
-retry_sector(buffer_struct ** p_buff, error_cause cause, int fdc_mode,
-	     unsigned skip)
-{
-	TRACE_FUN(8, "retry_sector");
-	buffer_struct *buff = *p_buff;
-
-	TRACEx1(4, "%s error, will retry",
-		(fdc_mode == fdc_writing_data) ? "write" : "read");
-	pause_tape(buff->segment_id, 1, fdc_mode);
-	runner_status = aborting;
-	buff->status = error;
-	buff->skip = skip;
-	TRACE_EXIT;
-}
-
-static unsigned
-find_resume_point(buffer_struct * buff)
-{
-	TRACE_FUN(8, "find_resume_point");
-	int i = 0;
-	unsigned long mask;
-	unsigned long map;
-
-	/*  This function is to be called after all variables have been
-	 *  updated to point past the failing sector.
-	 *  If there are any soft errors before the failing sector,
-	 *  find the first soft error and return the sector offset.
-	 *  Otherwise find the last hard error.
-	 *  Note: there should always be at least one hard or soft error !
-	 */
-	if (buff->sector_offset < 1 || buff->sector_offset > 32) {
-		TRACEx1(1, "bug: sector_offset = %d", buff->sector_offset);
-	} else {
-		if (buff->sector_offset >= 32) {	/* C-limitation on shift ! */
-			mask = 0xffffffff;
-		} else {
-			mask = (1 << buff->sector_offset) - 1;
-		}
-		map = buff->soft_error_map & mask;
-		if (map) {
-			while ((map & (1 << i)) == 0) {
-				++i;
-			}
-			TRACEx1(4, "at sector %d", SECTOR(i));
-		} else {
-			map = buff->hard_error_map & mask;
-			i = buff->sector_offset - 1;
-			if (map) {
-				while ((map & (1 << i)) == 0) {
-					--i;
-				}
-				TRACEx1(4, "after sector %d", SECTOR(i));
-				++i;	/* first sector after last hard error */
-			} else {
-				TRACE(1, "bug: no soft or hard errors");
-			}
-		}
-	}
-	TRACE_EXIT;
-	return i;
-}
-
-/*      FDC interrupt service routine.
- */
-void
-fdc_isr(void)
-{
-	TRACE_FUN(8, "fdc_isr");
-	int result;
-	int status;
-	error_cause cause = no_error;
-	byte in[7];
-	static int isr_active = 0;
-	int t0;
-	buffer_struct *buff = &buffer[head];
-	int skip;
-
-	t0 = timestamp();
-	if (isr_active) {
-		TRACE(-1, "nested interrupt, not good !");
-		*fdc.hook = fdc_isr;	/* hook our handler into the fdc code again */
-		TRACE_EXIT;
-		return;
-	}
-	++isr_active;
-	sti();			/* enables interrupts again */
-	status = inb_p(fdc.msr);
-	if (status & FDC_BUSY) {	/*  Entering Result Phase */
-		hide_interrupt = 0;
-		result = fdc_result(in, 7);	/* better get it fast ! */
-		if (result < 0) {
-			/*  Entered unknown state...
-			 */
-			TRACE(1, "probably fatal error during FDC Result Phase");
-			TRACE(1, "drive may hang until (power) reset :-(");
-			/*  what to do next ????
-			 */
-		} else {
-			int i;
-			char *fdc_mode_txt;
-
-			decode_irq_cause(fdc_mode, in, &fdc_mode_txt, &cause);
-			for (i = 0; i < NR_BUFFERS; ++i) {
-				TRACEx3(8, "buffer[%d] status: %d, segment_id: %d",
-					i, buffer[i].status, buffer[i].segment_id);
-			}
-			switch (fdc_mode) {
-
-			case fdc_reading_data:{
-
-					if (cause == no_error) {
-						TRACEi(5, "reading segment", buff->segment_id);
-					} else {
-						TRACEi(4, "error reading segment", buff->segment_id);
-					}
-					if (runner_status == aborting || runner_status == do_abort) {
-						TRACEx1(4, "aborting %s", fdc_mode_txt);
-						break;
-					}
-					if (buff->retry > 0) {
-						TRACEx1(5, "this is retry nr %d", buff->retry);
-					}
-					if (buff->bad_sector_map == FAKE_SEGMENT) {
-						/* This condition occurs when reading a `fake' sector that's
-						 * not accessible. Doesn't really matter as we would have
-						 * ignored it anyway !
-						 * Chance is that we're past the next segment now, so the
-						 * next operation may fail and result in a retry.
-						 */
-						TRACE(4, "skipping empty segment (read)");
-						buff->remaining = 0;	/* skip failing sector */
-						continue_xfer(&buff, no_error, fdc_mode, 1);	/* fake success */
-					} else {
-						switch (cause) {
-						case no_error:{
-								determine_progress(buff, cause, fdc_reading_data);
-								if (in[2] & 0x40) {
-									/*  Handle deleted data in header segments.
-									 *  Skip segment and force read-ahead.
-									 */
-									TRACEx1(2, "deleted data in sector %d",
-										SECTOR(buff->sector_offset - 1));
-									buff->deleted = 1;
-									buff->remaining = 0;	/* abort transfer */
-									buff->soft_error_map |= (-1L << buff->sector_offset);
-									if (buff->segment_id == 0) {
-										stop_read_ahead = 1;	/* stop on next segment */
-									}
-									buff->next_segment = buff->segment_id + 1;	/* force read-ahead */
-									skip = (SECTORS_PER_SEGMENT - buff->sector_offset);
-								} else {
-									skip = 0;
-								}
-								continue_xfer(&buff, cause, fdc_mode, skip);
-								break;
-							}
-						case no_data_error:
-							/*  Tape started too far ahead of or behind the right sector.
-							 *  This may also happen in the middle of a segment !
-							 *  Handle no-data as soft error. If next sector fails too,
-							 *  a retry (with needed reposition) will follow.
-							 */
-						case id_am_error:
-						case id_crc_error:
-						case data_am_error:
-						case data_crc_error:
-						case overrun_error:{
-								int first_error = (buff->soft_error_map == 0 &&
-										   buff->hard_error_map == 0);
-
-								update_history(cause);
-								determine_progress(buff, cause, fdc_reading_data);
-								if (first_error) {
-									skip = buff->sector_offset;
-								} else {
-									skip = find_resume_point(buff);
-								}
-								/*  Try to resume with next sector on single errors (let ecc
-								 *  correct it), but retry on no_data (we'll be past the
-								 *  target when we get here so we cannot retry) or on multiple
-								 *  errors (reduce chance on ecc failure).
-								 */
-								if (first_error && cause != no_data_error) {
-									continue_xfer(&buff, cause, fdc_mode, skip);
-								} else {
-									retry_sector(&buff, cause, fdc_mode, skip);
-								}
-								break;
-							}
-						default:{
-								/*  Don't know why this could happen but find out.
-								 */
-								TRACE(1, "unexpected error");
-								determine_progress(buff, cause, fdc_reading_data);
-								retry_sector(&buff, cause, fdc_mode, 0);
-								break;
-							}
-						}
-					}
-					break;
-				}
-
-			case fdc_reading_id:{
-
-					if (cause == no_error) {
-						fdc_cyl = in[3];
-						fdc_head = in[4];
-						fdc_sect = in[5];
-						TRACEx3(6, "id read: C: 0x%02x, H: 0x%02x, R: 0x%02x",
-							fdc_cyl, fdc_head, fdc_sect);
-					} else {	/* no valid information, use invalid sector */
-						fdc_cyl =
-						    fdc_head =
-						    fdc_sect = 0;
-						TRACE(5, "Didn't find valid sector Id");
-					}
-					fdc_mode = fdc_idle;
-					break;
-				}
-
-			case fdc_writing_data:{
-
-					if (cause == no_error) {
-						TRACEi(5, "writing segment", buff->segment_id);
-					} else {
-						TRACEi(4, "error writing segment", buff->segment_id);
-					}
-					if (runner_status == aborting || runner_status == do_abort) {
-						TRACEx1(5, "aborting %s", fdc_mode_txt);
-						break;
-					}
-					if (buff->retry > 0) {
-						TRACEx1(5, "this is retry nr %d", buff->retry);
-					}
-					if (buff->bad_sector_map == FAKE_SEGMENT) {
-						/* This condition occurs when trying to write to a `fake'
-						 * sector that's not accessible. Doesn't really matter as
-						 * it isn't used anyway ! Might be located at wrong segment,
-						 * then we'll fail on the next segment.
-						 */
-						TRACE(4, "skipping empty segment (write)");
-						buff->remaining = 0;	/* skip failing sector */
-						continue_xfer(&buff, no_error, fdc_mode, 1);	/* fake success */
-					} else {
-						switch (cause) {
-						case no_error:{
-								determine_progress(buff, cause, fdc_writing_data);
-								continue_xfer(&buff, cause, fdc_mode, 0);
-								break;
-							}
-						case no_data_error:
-						case id_am_error:
-						case id_crc_error:
-						case data_am_error:
-						case overrun_error:{
-								update_history(cause);
-								determine_progress(buff, cause, fdc_writing_data);
-								skip = find_resume_point(buff);
-								retry_sector(&buff, cause, fdc_mode, skip);
-								break;
-							}
-						default:{
-								if (in[1] & 0x02) {
-									TRACE(1, "media not writable");
-								} else {
-									TRACE(-1, "unforeseen write error");
-								}
-								fdc_mode = fdc_idle;
-								break;
-							}
-						}
-					}
-					break;
-				}
-			default:
-
-				TRACEx1(1, "Warning: unexpected irq during: %s",
-					fdc_mode_txt);
-				fdc_mode = fdc_idle;
-				break;
-			}
-		}
-		if (runner_status == do_abort) {
-			/*      cease operation, remember tape position
-			 */
-			TRACE(5, "runner aborting");
-			runner_status = aborting;
-			++expected_stray_interrupts;
-		}
-	} else { /* !FDC_BUSY  */
-		/*  clear interrupt, cause should be gotten by issuing
-		 *  a Sense Interrupt Status command.
-		 */
-		if (fdc_mode == fdc_recalibrating || fdc_mode == fdc_seeking) {
-			if (hide_interrupt) {
-				int st0;
-				int pcn;
-
-				result = fdc_sense_interrupt_status(&st0, &pcn);
-				current_cylinder = pcn;
-				TRACE(5, "handled hidden interrupt");
-			}
-			seek_completed = 1;
-			fdc_mode = fdc_idle;
-		} else if (!waitqueue_active(&wait_intr)) {
-			if (expected_stray_interrupts == 0) {
-				TRACE(2, "unexpected stray interrupt");
-			} else {
-				TRACE(5, "expected stray interrupt");
-				--expected_stray_interrupts;
-			}
-		} else {
-			if (fdc_mode == fdc_reading_data || fdc_mode == fdc_writing_data ||
-			    fdc_mode == fdc_reading_id) {
-				byte status = inb_p(fdc.msr);
-				if (status & FDC_BUSY) {
-					TRACE(-1, "***** FDC failure, busy too late");
-				} else {
-					TRACE(-1, "***** FDC failure, no busy");
-				}
-			} else {
-				TRACE(6, "awaited stray interrupt");
-			}
-		}
-		hide_interrupt = 0;
-	}
-	/*    Handle sleep code.
-	 */
-	if (!hide_interrupt) {
-		++interrupt_seen;
-		if (wait_intr) {
-			wake_up_interruptible(&wait_intr);
-		}
-	} else {
-		TRACEx1(5, "hiding interrupt while %s", wait_intr ? "waiting" : "active");
-	}
-	t0 = timediff(t0, timestamp());
-	if (t0 >= 1000) {	/* only tell us about long calls */
-		TRACEx1(7, "isr() duration: %5d usec", t0);
-	}
-	*fdc.hook = fdc_isr;	/* hook our handler into the fdc code again */
-	TRACE_EXIT;
-	--isr_active;
-}

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov