Re: PATCH: [2.4.21-pre3] IDE error recovery

[Ross Biro <rossb@google.com>]

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Someone said there were word wrapping problems with my mailer.  I'm too 
lazy to get a real mailer, so here's an attachment.

       Ross


Ross Biro wrote:

>
> Take this patch with a big grain of salt.
>
> The current IDE error recovery code will send a IDLEIMMEDIATE in the 
> case when a drive is still busy or has drq set during an error.  This 
> is a violation of the ATA spec and hoses up quite a few drives.  The 
> prefered form of error recovery seems to be a soft reset followed by a 
> set features.  This patch replaces the IDLEIMMEDIATE with a reset, but 
> does not do the set features.  The set features should not be 
> necessary, but at least one drive vendor does most of their testing 
> with the set features.  OK_TO_RESET_CONTROLLER must be set to 1 if 
> this patch is applied.
>
> I've modified the google kernel to add a desired_speed to ide_drive_t 
> and check to see if current_speed != desired_speed before every read 
> or write request.  This causes a set features after a reset.  I can 
> provide patches to do something similiar for 2.4.21, but I'm not sure 
> it's appropriate.  There are bugs in the way hdparm -X is handled in 
> 2.4.20, and this patch would fix them as well, but it may be too large 
> of a patch for a stable kernel.
>
> This also fixes drive_cmd_intr to do a little better checking to make 
> sure the device is ready.  The spec requires this, but any device that 
> sends an interrupt before it's ready is probably broken.
>
> I have no idea what impact this will have on older devices or non disks.
>
> This patch has only been minimally tested.
>
> ----- snip -------
> diff -durbB linux-2.4.20-p1/drivers/ide/ide-cd.c 
> linux-2.4.20-p2/drivers/ide/ide-cd.c
> --- linux-2.4.20-p1/drivers/ide/ide-cd.c    Wed Jan  8 16:25:04 2003
> +++ linux-2.4.20-p2/drivers/ide/ide-cd.c    Thu Jan  9 11:38:22 2003
> @@ -644,7 +644,11 @@
>     }
>     if (HWIF(drive)->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT)) {
>         /* force an abort */
> -        HWIF(drive)->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);
> +                /* This violates the ATA Spec and causes trouble for
> +                   many modern hard drives.  I'm not sure if it is 
> necessary
> +                   for older devices or even modern cd-roms. -- RAB
> +                   
> HWIF(drive)->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG); */
> +                rq->errors |= ERROR_RESET;
>         }
>     if (rq->errors >= ERROR_MAX) {
>         DRIVER(drive)->end_request(drive, 0);
> diff -durbB linux-2.4.20-p1/drivers/ide/ide-disk.c 
> linux-2.4.20-p2/drivers/ide/ide-disk.c
> --- linux-2.4.20-p1/drivers/ide/ide-disk.c    Wed Jan  8 16:25:17 2003
> +++ linux-2.4.20-p2/drivers/ide/ide-disk.c    Thu Jan  9 11:40:20 2003
> @@ -943,7 +943,11 @@
>     }
>     if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT)) {
>         /* force an abort */
> -        hwif->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);
> +                /* This violates the ATA Spec and causes trouble for
> +                   many modern hard drives.  I'm not sure if it is 
> necessary
> +                   for older devices or even other modern devices. -- 
> RAB
> +                   hwif->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG); */
> +                rq->errors |= ERROR_RESET;
>     }
>     if (rq->errors >= ERROR_MAX)
>         DRIVER(drive)->end_request(drive, 0);
> diff -durbB linux-2.4.20-p1/drivers/ide/ide-io.c 
> linux-2.4.20-p2/drivers/ide/ide-io.c
> --- linux-2.4.20-p1/drivers/ide/ide-io.c    Wed Jan  8 16:25:37 2003
> +++ linux-2.4.20-p2/drivers/ide/ide-io.c    Mon Jan 13 18:01:52 2003
> @@ -328,7 +328,12 @@
>     }
>     if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT)) {
>         /* force an abort */
> +                /* This violates the ATA Spec and causes trouble for
> +                   many modern hard drives.  I'm not sure if it is 
> necessary
> +                   for older devices or even other modern ata devices 
> -- RAB
>         hwif->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);
> +                */
> +                rq->errors |= ERROR_RESET;
>     }
>     if (rq->errors >= ERROR_MAX) {
>         if (drive->driver != NULL)
> @@ -397,18 +402,63 @@
>     struct request *rq = HWGROUP(drive)->rq;
>     ide_hwif_t *hwif = HWIF(drive);
>     u8 *args = (u8 *) rq->buffer;
> -    u8 stat = hwif->INB(IDE_STATUS_REG);
> +    u8 stat;
>     int retries = 10;
>
> +        /* The ATA-6 spec requires a 400ns wait when entering the
> +           HPIOI1: Check_status State from the HI4 state.  We should
> +           only get here coming from the HPIOI0 INTRQ_wait state, but
> +           better safe than sorry.  The spec also says a read of the
> +           alt status register accomplishes this wait. */
> +    if (IDE_CONTROL_REG)
> +        (void)hwif->INB(IDE_ALTSTATUS_REG);
> +    else
> +                ide_delay_400ns();
> +
> +        /* The ATA-6 spec says that the should enter the check status
> +           state when it get's an interrupt for a drive command, so
> +           technically, the device can send an interrupt before it has
> +           finished.  I would consider any device that does this to be
> +           broken, but the spec allows it. --RAB 1/10/03 */
> +    stat = hwif->INB(IDE_STATUS_REG);
> +        if (stat & BUSY_STAT) {
> +                /* We are just supposed to poll from here on out. */
> +                if (HWGROUP(drive)->poll_timeout == 0) {
> +                        
> HWGROUP(drive)->poll_timeout=WAIT_CMD/CMD_POLL_TICKS;
> +                } else if (--HWGROUP(drive)->poll_timeout == 0) {
> +                        return DRIVER(drive)->error(drive,
> +                                                    "drive_cmd timeout",
> +                                                    stat);
> +                }
> +                ide_set_handler(drive, drive_cmd_intr, 
> CMD_POLL_TICKS, NULL);
> +                return ide_started;
> +        }
> +
>     local_irq_enable();
> -    if ((stat & DRQ_STAT) && args && args[3]) {
> +
> +        /* We want to make sure that the device and the command
> +           both agree on wether or not data is returned by the command
> +           that was just issued.  If they do not, it is an error. */
> +        if (args && args[3]) {
>         u8 io_32bit = drive->io_32bit;
> +                /* The software expects some data back.  If the drive 
> does
> +                   not, then it is an error. */
> +                if (!(stat & DRQ_STAT)) {
> +                        return DRIVER(drive)->error(drive, "drive_cmd 
> no data", stat);
> +                }
>         drive->io_32bit = 0;
>         hwif->ata_input_data(drive, &args[4], args[3] * SECTOR_WORDS);
>         drive->io_32bit = io_32bit;
>         while (((stat = hwif->INB(IDE_STATUS_REG)) & BUSY_STAT) && 
> retries--)
>             udelay(100);
> +        } else {
> +                /* The software does not expect data, so if the drive
> +                   returns some, then it's an error. */
> +                if (stat & DRQ_STAT) {
> +                        return DRIVER(drive)->error(drive, "drive_cmd 
> unexpected data", stat);
> +                }
>     }
> +
>
>     if (!OK_STAT(stat, READY_STAT, BAD_STAT))
>         return DRIVER(drive)->error(drive, "drive_cmd", stat);
> diff -durbB linux-2.4.20-p1/drivers/ide/ide-taskfile.c 
> linux-2.4.20-p2/drivers/ide/ide-taskfile.c
> --- linux-2.4.20-p1/drivers/ide/ide-taskfile.c    Wed Jan  8 16:25:43 
> 2003
> +++ linux-2.4.20-p2/drivers/ide/ide-taskfile.c    Fri Jan 10 11:19:07 
> 2003
> @@ -485,7 +485,13 @@
>     }
>     if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT)) {
>         /* force an abort */
> -        hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG);
> +                /* This violates the ATA Spec and causes trouble for
> +                   many modern hard drives.  I'm not sure if it is 
> necessary
> +                   for older devices or even other modern ata devices 
> -- RAB
> +        hwif->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);
> +                */
> +                rq->errors |= ERROR_RESET;
> +
>     }
>     if (rq->errors >= ERROR_MAX) {
>         DRIVER(drive)->end_request(drive, 0);
> diff -durbB linux-2.4.20-p1/include/linux/ide.h 
> linux-2.4.20-p2/include/linux/ide.h
> --- linux-2.4.20-p1/include/linux/ide.h    Thu Jan  9 15:37:22 2003
> +++ linux-2.4.20-p2/include/linux/ide.h    Mon Jan 13 18:04:47 2003
> @@ -271,6 +271,10 @@
> #define WAIT_WORSTCASE    (30*HZ)    /* 30sec  - worst case when 
> spinning up */
> #define WAIT_CMD    (10*HZ)    /* 10sec  - maximum wait for an IRQ to 
> happen */
> #define WAIT_MIN_SLEEP    (2*HZ/100)    /* 20msec - minimum sleep time */
> +#define CMD_POLL_TICKS  (1)     /* How long to wait in ticks between
> +                                   status checks for a drive cmd
> +                                   that set it's interrupt before it
> +                                   was complete. */
>
> #define HOST(hwif,chipset)                    \
> {                                \
>
>
> -
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