Re: ata_piix 2.6.25 sata failure

[Tejun Heo <htejun@gmail.com>]

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Matthieu CASTET wrote:
> Hi Tejun,
> 
> Matthieu CASTET wrote:
>> Hi,
>>
>> the 2.6.25 from debian fail to make work the second port. I got a 
>> "SATA link down (SStatus 61 Scontrol 30)" for ata2. ata1 got "SATA 
>> link up 3.0 Gbps (SStatus 13 SControl 30)"
>> The 2.6.24 works [1]. But some previous kernel (IRRC 2.6.18) had the 
>> same problem, ie ata2 doesn't work.
>>
> I saw you post a patch for macbook for correcting a bug with ata_ppiix.
> But it doesn't seem the same problem. I don't get 0 but others values.
> 
> May be a problem occurs when merging the master and slave status register ?
> 
> 
> Any idea how to debug this.
> 
> For information this happen on a HP Compaq dc7700p, and there no way on 
> the bios to change the controller to ahci mode

Yeah, I wrote a patch for that yesterday and forgot to actually send it. 
  Can you please test the attached patch?

-- 
tejun

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From: Tejun Heo <teheo@suse.de>
Subject: libata: force hardreset if link is in powersave mode
References: 381795

Inhibiting link PM mode doesn't bring the link back online if it's
already in powersave mode.  If SRST is used in these cases, libata EH
thinks that the link is offline and fails detection.  Force hardreset
if link is in powersave mode.

Signed-off-by: Tejun Heo <teheo@suse.de>
---
 drivers/ata/libata-core.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

Index: linux-2.6.25/drivers/ata/libata-core.c
===================================================================
--- linux-2.6.25.orig/drivers/ata/libata-core.c
+++ linux-2.6.25/drivers/ata/libata-core.c
@@ -3960,6 +3960,7 @@ int ata_std_prereset(struct ata_link *li
 	struct ata_port *ap = link->ap;
 	struct ata_eh_context *ehc = &link->eh_context;
 	const unsigned long *timing = sata_ehc_deb_timing(ehc);
+	u32 sstatus;
 	int rc;
 
 	/* handle link resume */
@@ -3973,6 +3974,17 @@ int ata_std_prereset(struct ata_link *li
 	if (ap->flags & ATA_FLAG_PMP)
 		ehc->i.action |= ATA_EH_HARDRESET;
 
+	/* if link powersave is on, force hardreset */
+	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0) {
+		u8 ipm = sstatus >> 8;
+
+		if (ipm == 2 || ipm == 6) {
+			ata_link_printk(link, KERN_INFO, "link in powersave "
+				"mode (ipm=%d), forcing hardreset\n", ipm);
+			ehc->i.action |= ATA_EH_HARDRESET;
+		}
+	}
+
 	/* if we're about to do hardreset, nothing more to do */
 	if (ehc->i.action & ATA_EH_HARDRESET)
 		return 0;