Commit f1a58eca authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

[PATCH] ata_piix: fix ghost device probing by honoring PCS present bits 



Move out PCS handling from piix_sata_prereset() into
piix_sata_present_mask() and use it from newly implemented
piix_sata_softreset().  Class codes for devices which are indicated to
be absent by PCS are cleared to ATA_DEV_NONE.  This fixes ghost device
problem reported on ICH6 and 7.

This patch moves PCS handling from prereset to softreset, which makes
two behavior changes.

* perform softreset even when PCS indicates no device
* PCS handling is repeated before retrying softresets due to reset
  failures.

Both behavior changes are intended and more consistent with how other
drivers behave.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent d14b50cc

drivers/scsi/ata_piix.c

+43 −17
Original line number Diff line number Diff line
@@ -531,27 +531,25 @@ static void piix_pata_error_handler(struct ata_port *ap) 
}



/**

 *	piix_sata_prereset - prereset for SATA host controller

 *	piix_sata_present_mask - determine present mask for SATA host controller

 *	@ap: Target port

 *

 *	Reads and configures SATA PCI device's PCI config register

 *	Port Configuration and Status (PCS) to determine port and

 *	device availability.  Return -ENODEV to skip reset if no

 *	device is present.

 *	Reads SATA PCI device's PCI config register Port Configuration

 *	and Status (PCS) to determine port and device availability.

 *

 *	LOCKING:

 *	None (inherited from caller).

 *

 *	RETURNS:

 *	0 if device is present, -ENODEV otherwise.

 *	determined present_mask

 */

static int piix_sata_prereset(struct ata_port *ap)

static unsigned int piix_sata_present_mask(struct ata_port *ap)

{

	struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);

	struct piix_host_priv *hpriv = ap->host_set->private_data;

	const unsigned int *map = hpriv->map;

	int base = 2 * ap->hard_port_no;

	unsigned int present = 0;

	unsigned int present_mask = 0;

	int port, i;

	u16 pcs;
@@ -564,24 +562,52 @@ static int piix_sata_prereset(struct ata_port *ap) 
			continue;

		if ((ap->flags & PIIX_FLAG_IGNORE_PCS) ||

		    (pcs & 1 << (hpriv->map_db->present_shift + port)))

			present = 1;

			present_mask |= 1 << i;

	}



	DPRINTK("ata%u: LEAVE, pcs=0x%x present=0x%x\n",

		ap->id, pcs, present);

	DPRINTK("ata%u: LEAVE, pcs=0x%x present_mask=0x%x\n",

		ap->id, pcs, present_mask);



	if (!present) {

		ata_port_printk(ap, KERN_INFO, "SATA port has no device.\n");

		ap->eh_context.i.action &= ~ATA_EH_RESET_MASK;

		return 0;

	return present_mask;

}



	return ata_std_prereset(ap);

/**

 *	piix_sata_softreset - reset SATA host port via ATA SRST

 *	@ap: port to reset

 *	@classes: resulting classes of attached devices

 *

 *	Reset SATA host port via ATA SRST.  On controllers with

 *	reliable PCS present bits, the bits are used to determine

 *	device presence.

 *

 *	LOCKING:

 *	Kernel thread context (may sleep)

 *

 *	RETURNS:

 *	0 on success, -errno otherwise.

 */

static int piix_sata_softreset(struct ata_port *ap, unsigned int *classes)

{

	unsigned int present_mask;

	int i, rc;



	present_mask = piix_sata_present_mask(ap);



	rc = ata_std_softreset(ap, classes);

	if (rc)

		return rc;



	for (i = 0; i < ATA_MAX_DEVICES; i++) {

		if (!(present_mask & (1 << i)))

			classes[i] = ATA_DEV_NONE;

	}



	return 0;

}



static void piix_sata_error_handler(struct ata_port *ap)

{

	ata_bmdma_drive_eh(ap, piix_sata_prereset, ata_std_softreset, NULL,

	ata_bmdma_drive_eh(ap, ata_std_prereset, piix_sata_softreset, NULL,

			   ata_std_postreset);

}

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