IDE Power Management (Was: software suspend in 2.5.70-mm3)

Benjamin Herrenschmidt (benh@kernel.crashing.org)
04 Jun 2003 15:14:41 +0200


On Tue, 2003-06-03 at 19:04, Benjamin Herrenschmidt wrote:
> On Tue, 2003-06-03 at 16:08, Alan Cox wrote:

> > Still races. Ben's stuff is needed
>
> I have it working with some fixes from what I sent earlier, I'll
> repost that tonight or tomorrow, I need to extract that from
> a half-broken tree ;)

Ok, here is it. It still need a bit of cleanup (removal of magic
number for "steps" -> enum, etc...) and we may want to do more
things on wakeup especially for ide-cd, Also I don't deal with
ide-tape or ide-floppy in there and haven't fully studied the
impact with ide-scsi....

So it's not meant to be merged as-is, though I'd appreciate to
know if it helps for you.

Bartolomiej: Any comments appreciated, I won't do the ide-tape/floppy
part as I don't know/own these, I think i'll let you decide if
anything more is needed on the wakeup path for ide-cd... Once I
have enough feedback, I'll send you a cleanified version as
candidate for upstream merge.

===== drivers/ide/ide-cd.c 1.49 vs edited =====
--- 1.49/drivers/ide/ide-cd.c Sun Jun 1 21:55:45 2003
+++ edited/drivers/ide/ide-cd.c Wed Jun 4 14:53:38 2003
@@ -3253,6 +3253,46 @@

static int ide_cdrom_attach (ide_drive_t *drive);

+static void ide_cdrom_complete_power_step (ide_drive_t *drive, ide_power_state_t *state, u8 stat, u8 error)
+{
+}
+
+/* Power Management state machine.
+ *
+ * We don't do much for CDs right now
+ */
+static ide_startstop_t ide_cdrom_start_power_step (ide_drive_t *drive, ide_power_state_t *state)
+{
+ ide_task_t args;
+
+ memset(&args, 0, sizeof(ide_task_t));
+
+ if (state->step == 0) {
+ state->step = state->suspend ? 1 : 101;
+ return ide_stopped;
+ }
+ switch(state->step) {
+ case 1:
+ break;
+
+ case 101: /* Resume step 1 (restore DMA) */
+ /* Right now, all we do is call ide_dma_check for the HWIF,
+ * we could be smarter and check for current xfer_speed
+ * in struct drive etc...
+ * Also, this step could be implemented as a generic helper
+ * as most subdrivers will use it
+ */
+ if (!drive->id || !(drive->id->capability & 1))
+ break;
+ if (HWIF(drive)->ide_dma_check == NULL)
+ break;
+ HWIF(drive)->ide_dma_check(drive);
+ break;
+ }
+ state->step = ide_power_state_completed;
+ return ide_stopped;
+}
+
static ide_driver_t ide_cdrom_driver = {
.owner = THIS_MODULE,
.name = "ide-cdrom",
@@ -3269,6 +3309,12 @@
.capacity = ide_cdrom_capacity,
.attach = ide_cdrom_attach,
.drives = LIST_HEAD_INIT(ide_cdrom_driver.drives),
+ .start_power_step = ide_cdrom_start_power_step,
+ .complete_power_step = ide_cdrom_complete_power_step,
+ .gen_driver = {
+ .suspend = generic_ide_suspend,
+ .resume = generic_ide_resume,
+ }
};

static int idecd_open(struct inode * inode, struct file * file)
===== drivers/ide/ide-disk.c 1.45 vs edited =====
--- 1.45/drivers/ide/ide-disk.c Sun Jun 1 21:55:48 2003
+++ edited/drivers/ide/ide-disk.c Wed Jun 4 14:54:24 2003
@@ -138,8 +138,6 @@

#ifndef CONFIG_IDE_TASKFILE_IO

-static int driver_blocked;
-
/*
* read_intr() is the handler for disk read/multread interrupts
*/
@@ -364,9 +362,6 @@

nsectors.all = (u16) rq->nr_sectors;

- if (driver_blocked)
- panic("Request while ide driver is blocked?");
-
if (drive->using_tcq && idedisk_start_tag(drive, rq)) {
if (!ata_pending_commands(drive))
BUG();
@@ -1392,21 +1387,6 @@
return 0;
}

-static int call_idedisk_standby (ide_drive_t *drive, int arg)
-{
- ide_task_t args;
- u8 standby = (arg) ? WIN_STANDBYNOW2 : WIN_STANDBYNOW1;
- memset(&args, 0, sizeof(ide_task_t));
- args.tfRegister[IDE_COMMAND_OFFSET] = standby;
- args.command_type = ide_cmd_type_parser(&args);
- return ide_raw_taskfile(drive, &args, NULL);
-}
-
-static int do_idedisk_standby (ide_drive_t *drive)
-{
- return call_idedisk_standby(drive, 0);
-}
-
static int do_idedisk_flushcache (ide_drive_t *drive)
{
ide_task_t args;
@@ -1505,37 +1485,66 @@
#endif
}

-static int idedisk_suspend(struct device *dev, u32 state, u32 level)
-{
- ide_drive_t *drive = dev->driver_data;
-
- printk("Suspending device %p\n", dev->driver_data);
-
- /* I hope that every freeze operation from the upper levels have
- * already been done...
- */
-
- if (level != SUSPEND_SAVE_STATE)
- return 0;
-
- /* set the drive to standby */
- printk(KERN_INFO "suspending: %s ", drive->name);
- do_idedisk_standby(drive);
- drive->blocked = 1;

- BUG_ON (HWGROUP(drive)->handler);
- return 0;
+static void idedisk_complete_power_step (ide_drive_t *drive, ide_power_state_t *state, u8 stat, u8 error)
+{
+ switch(state->step) {
+ case 1: /* Suspend step 1 (flush cache) complete */
+ state->step = 2;
+ break;
+ case 2: /* Suspend step 2 (standby) complete */
+ state->step = ide_power_state_completed;
+ break;
+ }
}

-static int idedisk_resume(struct device *dev, u32 level)
+/* Power Management state machine. This one is rather trivial for now,
+ * we should probably add more, like switching back to PIO on suspend
+ * to help some BIOSes, re-do the door locking on resume, etc...
+ */
+static ide_startstop_t idedisk_start_power_step (ide_drive_t *drive, ide_power_state_t *state)
{
- ide_drive_t *drive = dev->driver_data;
+ ide_task_t args;

- if (level != RESUME_RESTORE_STATE)
- return 0;
- BUG_ON(!drive->blocked);
- drive->blocked = 0;
- return 0;
+ memset(&args, 0, sizeof(ide_task_t));
+
+ if (state->step == 0) {
+ state->step = state->suspend ? 1 : 101;
+ return ide_stopped;
+ }
+ switch(state->step) {
+ case 1: /* Suspend step 1 (flush cache) */
+ if (!drive->wcache) {
+ idedisk_complete_power_step(drive, state, 0, 0);
+ return ide_stopped;
+ }
+ if (drive->id->cfs_enable_2 & 0x2400)
+ args.tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE_EXT;
+ else
+ args.tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE;
+ args.command_type = ide_cmd_type_parser(&args);
+ return do_rw_taskfile(drive, &args);
+ case 2: /* Suspend step 2 (standby) */
+ args.tfRegister[IDE_COMMAND_OFFSET] = WIN_STANDBYNOW1;
+ args.command_type = ide_cmd_type_parser(&args);
+ return do_rw_taskfile(drive, &args);
+
+ case 101: /* Resume step 1 (restore DMA) */
+ /* Right now, all we do is call ide_dma_check for the HWIF,
+ * we could be smarter and check for current xfer_speed
+ * in struct drive etc...
+ * Also, this step could be implemented as a generic helper
+ * as most subdrivers will use it
+ */
+ if (!drive->id || !(drive->id->capability & 1))
+ break;
+ if (HWIF(drive)->ide_dma_check == NULL)
+ break;
+ HWIF(drive)->ide_dma_check(drive);
+ break;
+ }
+ state->step = ide_power_state_completed;
+ return ide_stopped;
}

static void idedisk_setup (ide_drive_t *drive)
@@ -1681,9 +1690,11 @@
.proc = idedisk_proc,
.attach = idedisk_attach,
.drives = LIST_HEAD_INIT(idedisk_driver.drives),
+ .start_power_step = idedisk_start_power_step,
+ .complete_power_step = idedisk_complete_power_step,
.gen_driver = {
- .suspend = idedisk_suspend,
- .resume = idedisk_resume,
+ .suspend = generic_ide_suspend,
+ .resume = generic_ide_resume,
}
};

===== drivers/ide/ide-io.c 1.11 vs edited =====
--- 1.11/drivers/ide/ide-io.c Mon May 12 02:09:46 2003
+++ edited/drivers/ide/ide-io.c Wed Jun 4 14:55:06 2003
@@ -139,6 +139,39 @@
EXPORT_SYMBOL(ide_end_request);

/**
+ * ide_complete_pm_request - end the current Power Management request
+ * @drive: target drive
+ * @rq: request
+ *
+ * This function cleans up the current PM request and stops the queue
+ * if necessary.
+ */
+
+static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
+{
+ ide_power_state_t *state = (ide_power_state_t *)rq->special;
+ unsigned long flags;
+ int suspend = state->suspend;
+
+#ifdef DEBUG_PM
+ printk("%s: completing PM request, suspend: %d\n", drive->name, state->suspend);
+#endif
+ spin_lock_irqsave(&ide_lock, flags);
+ if (suspend)
+ __blk_stop_queue(&drive->queue);
+ else
+ drive->blocked = 0;
+ blkdev_dequeue_request(rq);
+ HWGROUP(drive)->rq = NULL;
+ end_that_request_last(rq);
+ spin_unlock_irqrestore(&ide_lock, flags);
+ /* Hrm... there is no __blk_start_queue... */
+ if (!suspend)
+ blk_start_queue(&drive->queue);
+}
+
+
+/**
* ide_end_drive_cmd - end an explicit drive command
* @drive: command
* @stat: status bits
@@ -214,6 +247,17 @@
args->hobRegister[IDE_HCYL_OFFSET_HOB] = hwif->INB(IDE_HCYL_REG);
}
}
+ } else if (rq->flags & REQ_POWER_MANAGEMENT) {
+ ide_power_state_t *state = (ide_power_state_t *)rq->special;
+
+#ifdef DEBUG_PM
+ printk("%s: complete_power_step(susp: %d, step: %d, stat: %x, err: %x)\n",
+ drive->name, state->suspend, state->step, stat, err);
+#endif
+ DRIVER(drive)->complete_power_step(drive, state, stat, err);
+ if (state->step == ide_power_state_completed)
+ ide_complete_pm_request(drive, rq);
+ return;
}

spin_lock_irqsave(&ide_lock, flags);
@@ -615,7 +659,37 @@
while ((read_timer() - HWIF(drive)->last_time) < DISK_RECOVERY_TIME);
#endif

- SELECT_DRIVE(drive);
+ if (rq->flags & REQ_POWER_MANAGEMENT) {
+ ide_power_state_t *state = (ide_power_state_t *)rq->special;
+ int rc;
+
+ /* Mark drive blocked when starting the suspend sequence */
+ if (state->suspend && state->step == 0)
+ drive->blocked = 1;
+ /* If this is a power management wakeup request, the first thing
+ * we do is to wait for BSY bit to go away (with a looong timeout)
+ * as a drive on this hwif may just be POSTing itself. We do that
+ * before even selecting as the "other" device on the bus may be
+ * broken enough to walk on our toes at this point.
+ */
+ if (state->suspend != 0 || state->step != 0)
+ goto dont_wait;
+#ifdef DEBUG_PM
+ printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
+#endif
+ rc = ide_wait_not_busy(HWIF(drive), 35000);
+ if (rc)
+ printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
+ SELECT_DRIVE(drive);
+ HWIF(drive)->OUTB(8, HWIF(drive)->io_ports[IDE_CONTROL_OFFSET]);
+ rc = ide_wait_not_busy(HWIF(drive), 10000);
+ if (rc)
+ printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
+ } else {
+dont_wait:
+ SELECT_DRIVE(drive);
+ }
+
if (ide_wait_stat(&startstop, drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) {
printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
return startstop;
@@ -625,6 +699,19 @@
return execute_drive_cmd(drive, rq);
else if (rq->flags & REQ_DRIVE_TASKFILE)
return execute_drive_cmd(drive, rq);
+ else if (rq->flags & REQ_POWER_MANAGEMENT) {
+ ide_power_state_t *state = (ide_power_state_t *)rq->special;
+
+#ifdef DEBUG_PM
+ printk("%s: start_power_step(susp: %d, step: %d)\n", drive->name, state->suspend, state->step);
+#endif
+ startstop = DRIVER(drive)->start_power_step(drive, state);
+ if (startstop == ide_stopped && state->step == ide_power_state_completed) {
+ ide_complete_pm_request(drive, rq);
+ return ide_stopped;
+ } else
+ return startstop;
+ }
return (DRIVER(drive)->do_request(drive, rq, block));
}
return do_special(drive);
@@ -837,6 +924,22 @@
break;
}

+ /* Sanity: don't accept a request that isn't a PM request
+ * if we are currently power managed. This is very important as
+ * blk_stop_queue() doesn't prevent the elv_next_request() above
+ * to return us whatever is in the queue. Since we call ide_do_request()
+ * ourselves, we end up taking requests while the queue is blocked...
+ */
+ if (drive->blocked && !(rq->flags & REQ_POWER_MANAGEMENT)) {
+#ifdef DEBUG_PM
+ printk("%s: a request made it's way while we are power managing...\n", drive->name);
+#endif
+ /* We clear busy, there should be no pending ATA command at this point
+ */
+ hwgroup->busy = 0;
+ break;
+ }
+
if (!rq->bio && ata_pending_commands(drive))
break;

@@ -1282,12 +1385,16 @@
ide_hwgroup_t *hwgroup = HWGROUP(drive);
DECLARE_COMPLETION(wait);
int insert_end = 1, err;
-
+ int must_wait = (action == ide_wait || action == ide_head_wait);
+
#ifdef CONFIG_BLK_DEV_PDC4030
/*
* FIXME: there should be a drive or hwif->special
* handler that points here by default, not hacks
* in the ide-io.c code
+ *
+ * FIXME2: That code breaks power management if used with
+ * this chipset, that really doesn't belong here !
*/
if (HWIF(drive)->chipset == ide_pdc4030 && rq->buffer != NULL)
return -ENOSYS; /* special drive cmds not supported */
@@ -1301,13 +1408,13 @@
* we need to hold an extra reference to request for safe inspection
* after completion
*/
- if (action == ide_wait) {
+ if (must_wait) {
rq->ref_count++;
rq->waiting = &wait;
}

spin_lock_irqsave(&ide_lock, flags);
- if (action == ide_preempt) {
+ if (action == ide_preempt || action == ide_head_wait) {
hwgroup->rq = NULL;
insert_end = 0;
}
@@ -1316,7 +1423,7 @@
spin_unlock_irqrestore(&ide_lock, flags);

err = 0;
- if (action == ide_wait) {
+ if (must_wait) {
wait_for_completion(&wait);
if (rq->errors)
err = -EIO;
===== drivers/ide/ide-iops.c 1.17 vs edited =====
--- 1.17/drivers/ide/ide-iops.c Tue Mar 25 12:56:05 2003
+++ edited/drivers/ide/ide-iops.c Wed Jun 4 14:55:13 2003
@@ -1318,5 +1318,32 @@
return do_reset1(drive, 0);
}

+/*
+ * This function waits for the hwif to report a non-busy status
+ * see comments in probe_hwif()
+ */
+int ide_wait_not_busy(ide_hwif_t *hwif, unsigned long timeout)
+{
+ u8 stat = 0;
+
+ while(timeout--) {
+ /* Turn this into a schedule() sleep once I'm sure
+ * about locking issues (2.5 work ?)
+ */
+ mdelay(1);
+ stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
+ if ((stat & BUSY_STAT) == 0)
+ break;
+ /* Assume a value of 0xff means nothing is connected to
+ * the interface and it doesn't implement the pull-down
+ * resistor on D7
+ */
+ if (stat == 0xff)
+ break;
+ }
+ return ((stat & BUSY_STAT) == 0) ? 0 : -EBUSY;
+}
+
+
EXPORT_SYMBOL(ide_do_reset);

===== drivers/ide/ide-probe.c 1.49 vs edited =====
--- 1.49/drivers/ide/ide-probe.c Tue May 27 02:48:43 2003
+++ edited/drivers/ide/ide-probe.c Wed Jun 4 14:56:08 2003
@@ -723,35 +723,6 @@

//EXPORT_SYMBOL(hwif_register);

-/* Enable code below on all archs later, for now, I want it on PPC
- */
-#ifdef CONFIG_PPC
-/*
- * This function waits for the hwif to report a non-busy status
- * see comments in probe_hwif()
- */
-static int wait_not_busy(ide_hwif_t *hwif, unsigned long timeout)
-{
- u8 stat = 0;
-
- while(timeout--) {
- /* Turn this into a schedule() sleep once I'm sure
- * about locking issues (2.5 work ?)
- */
- mdelay(1);
- stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
- if ((stat & BUSY_STAT) == 0)
- break;
- /* Assume a value of 0xff means nothing is connected to
- * the interface and it doesn't implement the pull-down
- * resistor on D7
- */
- if (stat == 0xff)
- break;
- }
- return ((stat & BUSY_STAT) == 0) ? 0 : -EBUSY;
-}
-
static int wait_hwif_ready(ide_hwif_t *hwif)
{
int rc;
@@ -766,7 +737,7 @@
* I know of at least one disk who takes 31 seconds, I use 35
* here to be safe
*/
- rc = wait_not_busy(hwif, 35000);
+ rc = ide_wait_not_busy(hwif, 35000);
if (rc)
return rc;

@@ -774,20 +745,19 @@
SELECT_DRIVE(&hwif->drives[0]);
hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
mdelay(2);
- rc = wait_not_busy(hwif, 10000);
+ rc = ide_wait_not_busy(hwif, 10000);
if (rc)
return rc;
SELECT_DRIVE(&hwif->drives[1]);
hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
mdelay(2);
- rc = wait_not_busy(hwif, 10000);
+ rc = ide_wait_not_busy(hwif, 10000);

/* Exit function with master reselected (let's be sane) */
SELECT_DRIVE(&hwif->drives[0]);

return rc;
}
-#endif /* CONFIG_PPC */

/*
* This routine only knows how to look for drive units 0 and 1
===== drivers/ide/ide.c 1.70 vs edited =====
--- 1.70/drivers/ide/ide.c Sun Jun 1 21:50:38 2003
+++ edited/drivers/ide/ide.c Wed Jun 4 14:56:33 2003
@@ -1441,6 +1441,52 @@

EXPORT_SYMBOL(ata_attach);

+int generic_ide_suspend(struct device *dev, u32 state, u32 level)
+{
+ ide_drive_t *drive = dev->driver_data;
+ struct request rq;
+ ide_power_state_t args;
+
+ if (level == dev->power_state || level != SUSPEND_SAVE_STATE)
+ return 0;
+
+ /* The suspend request is a state machine of taskfile requests */
+ memset(&rq, 0, sizeof(rq));
+ memset(&args, 0, sizeof(args));
+ rq.flags = REQ_POWER_MANAGEMENT;
+ rq.special = &args;
+ args.step = 0;
+ args.suspend = 1;
+
+ /* Start it */
+ return ide_do_drive_cmd(drive, &rq, ide_wait);
+}
+
+EXPORT_SYMBOL(generic_ide_suspend);
+
+int generic_ide_resume(struct device *dev, u32 level)
+{
+ ide_drive_t *drive = dev->driver_data;
+ struct request rq;
+ ide_power_state_t args;
+
+ if (level == dev->power_state || level != RESUME_RESTORE_STATE)
+ return 0;
+
+ /* The suspend request is a state machine of taskfile requests */
+ memset(&rq, 0, sizeof(rq));
+ memset(&args, 0, sizeof(args));
+ rq.flags = REQ_POWER_MANAGEMENT;
+ rq.special = &args;
+ args.step = 0;
+ args.suspend = 0;
+
+ /* Start it */
+ return ide_do_drive_cmd(drive, &rq, ide_head_wait);
+}
+
+EXPORT_SYMBOL(generic_ide_resume);
+
int generic_ide_ioctl(struct block_device *bdev, unsigned int cmd,
unsigned long arg)
{
===== include/linux/blkdev.h 1.106 vs edited =====
--- 1.106/include/linux/blkdev.h Tue May 27 22:15:31 2003
+++ edited/include/linux/blkdev.h Wed Jun 4 14:58:00 2003
@@ -130,6 +130,7 @@
__REQ_DRIVE_CMD,
__REQ_DRIVE_TASK,
__REQ_DRIVE_TASKFILE,
+ __REQ_POWER_MANAGEMENT,
__REQ_NR_BITS, /* stops here */
};

@@ -151,6 +152,7 @@
#define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
#define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
#define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
+#define REQ_POWER_MANAGEMENT (1 << __REQ_POWER_MANAGEMENT)

#include <linux/elevator.h>

===== include/linux/ide.h 1.54 vs edited =====
--- 1.54/include/linux/ide.h Thu May 29 21:04:47 2003
+++ edited/include/linux/ide.h Wed Jun 4 14:57:33 2003
@@ -23,6 +23,8 @@
#include <asm/hdreg.h>
#include <asm/io.h>

+#define DEBUG_PM
+
/*
* This is the multiple IDE interface driver, as evolved from hd.c.
* It supports up to four IDE interfaces, on one or more IRQs (usually 14 & 15).
@@ -1144,6 +1146,39 @@
#endif

/*
+ * Power Management related definitions
+ */
+typedef struct ide_power_state_s
+{
+ int suspend; /* 1 = suspending, 0 = resuming */
+ int step; /* Step in PM state machine */
+ void* data; /* Any additional data the subdriver wants */
+} ide_power_state_t;
+
+#define ide_power_state_completed -1
+#define ide_power_state_first 0
+//#define ide_power_state_core_first 100
+//#define ide_power_state_core_last 199
+
+/* The step value starts at 0 (ide_power_state_first).
+ *
+ * For each step, the core calls the subdriver start_power_step()
+ * first. This can return
+ * - ide_stopped : In this case, the core calls us back again unless
+ * step have been set to ide_power_state_completed
+ * - ide_started : In this case, the channel is left busy until an
+ * async event (interrupt) occurs.
+ * Typically, start_power_step() will issue a taskfile request with
+ * do_rw_taskfile().
+ *
+ * Upon reception of the interrupt, the core will call complete_power_step()
+ * with the error code if any. This routine should update the step value
+ * and return. It should not start a new request. The core will call
+ * start_power_step for the new step value, unless step have been set to
+ * ide_power_state_completed.
+ */
+
+/*
* Subdrivers support.
*/
#define IDE_SUBDRIVER_VERSION 1
@@ -1172,6 +1207,8 @@
int (*attach)(ide_drive_t *);
void (*ata_prebuilder)(ide_drive_t *);
void (*atapi_prebuilder)(ide_drive_t *);
+ ide_startstop_t (*start_power_step)(ide_drive_t *, ide_power_state_t *state);
+ void (*complete_power_step)(ide_drive_t *, ide_power_state_t *state, u8 stat, u8 error);
struct device_driver gen_driver;
struct list_head drives;
struct list_head drivers;
@@ -1180,6 +1217,8 @@
#define DRIVER(drive) ((drive)->driver)

extern int generic_ide_ioctl(struct block_device *, unsigned, unsigned long);
+extern int generic_ide_suspend(struct device *dev, u32 state, u32 level);
+extern int generic_ide_resume(struct device *dev, u32 level);

/*
* IDE modules.
@@ -1321,6 +1360,7 @@
ide_wait, /* insert rq at end of list, and wait for it */
ide_next, /* insert rq immediately after current request */
ide_preempt, /* insert rq in front of current request */
+ ide_head_wait, /* insert rq in front of current request and wait for it */
ide_end /* insert rq at end of list, but don't wait for it */
} ide_action_t;

@@ -1531,6 +1571,7 @@
extern int set_transfer(ide_drive_t *, ide_task_t *);
extern int taskfile_lib_get_identify(ide_drive_t *drive, u8 *);

+extern int ide_wait_not_busy(ide_hwif_t *hwif, unsigned long timeout);
ide_startstop_t __ide_do_rw_disk(ide_drive_t *drive, struct request *rq, sector_t block);

/*

-
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