[PATCH #upstream-fixes] ahci: fix status register check in ahci_softreset

[PATCH #upstream-fixes] ahci: fix status register check in ahci_softreset

[Tejun Heo]

ahci_softreset() used to use ahci_tf_read() which reads D2H_REG area
to check for the Status register.  However, this area is zeroed on
initialization and not set by initial signature FIS.  Replace it with
ahci_check_status().

This bug prevented CLO code from being activated whenever BSY and/or
DRQ is set prior to softreset.  This fix makes
AHCI_FLAG_RESET_NEEDS_CLO flag redundant.

Signed-off-by: Tejun Heo <htejun@gmail.com>
---

Jeff, check_status fix is separated as requested.  Please apply to
#upstream-fixes.

Thanks.

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index cef2e70..988f8bb 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -736,8 +736,7 @@ static int ahci_softreset(struct ata_por
 	}
 
 	/* check BUSY/DRQ, perform Command List Override if necessary */
-	ahci_tf_read(ap, &tf);
-	if (tf.command & (ATA_BUSY | ATA_DRQ)) {
+	if (ahci_check_status(ap) & (ATA_BUSY | ATA_DRQ)) {
 		rc = ahci_clo(ap);
 
 		if (rc == -EOPNOTSUPP) {

Re: [PATCH #upstream-fixes] ahci: fix status register check in ahci_softreset

[Jeff Garzik]

Tejun Heo wrote:
> ahci_softreset() used to use ahci_tf_read() which reads D2H_REG area
> to check for the Status register.  However, this area is zeroed on
> initialization and not set by initial signature FIS.  Replace it with
> ahci_check_status().
> 
> This bug prevented CLO code from being activated whenever BSY and/or
> DRQ is set prior to softreset.  This fix makes
> AHCI_FLAG_RESET_NEEDS_CLO flag redundant.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

applied