[PATCH v2] Fix the dma state machine lockup for the ATA_CMD_SMART PIO mode command.

[PATCH v2] Fix the dma state machine lockup for the ATA_CMD_SMART PIO mode command.

[Suman Tripathi]

v1 changes:
 * Update the commit id as per Tejun's comments.
 * Add a bit explanation.

v2 changes:
 * Update the comments from sergei.

Signed-off-by: Suman Tripathi <stripathi@apm.com>
---

Suman Tripathi (1):
  ahci_xgene: Fix the dma state machine lockup for the ATA_CMD_SMART PIO
    mode command.

 drivers/ata/ahci_xgene.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--
1.8.2.1

[PATCH v2] ahci_xgene: Fix the dma state machine lockup for the ATA_CMD_SMART PIO mode command.

[Suman Tripathi]

This patch addresses the issue with ATA_CMD_SMART pio mode
command for enumeration and device detection with ATA devices.
The X-Gene AHCI controller has an errata in which it cannot clear
the BSY bit after the PIO setup FIS. The dma state machine enters
CMFatalErrorUpdate state and locks up. It is the same issue as
in the commit 2a0bdff6b958d1b2523d2754b6cd5e0ea4053016(fix the
dma state machine lockup for the IDENTIFY DEVICE PIO mode
command).

For example :  without this patch it results in READ DMA command failure
as show below :

 [  126.700072] ata2.00: exception Emask 0x0 SAct 0x0
		SErr 0x0 action 0x6 frozen
 [  126.707089] ata2.00: failed command: READ DMA
 [  126.711426] ata2.00: cmd c8/00:08:00:55:57/00:00:00:00:00/e1 tag 1
                dma 4096 in
 [  126.711426]  res 40/00:ff:00:00:00/00:00:00:00:00/40 Emask
		0x4 (timeout)
 [  126.725956] ata2.00: status: { DRDY }

Signed-off-by: Suman Tripathi <stripathi@apm.com>
Reported-by:   Mark Langsdorf <mlangsdo@redhat.com>
---
---
 drivers/ata/ahci_xgene.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
index 7f68875..506cf5f 100644
--- a/drivers/ata/ahci_xgene.c
+++ b/drivers/ata/ahci_xgene.c
@@ -211,7 +211,8 @@ static unsigned int xgene_ahci_qc_issue(struct ata_queued_cmd *qc)
 	}

 	if (unlikely((ctx->last_cmd[ap->port_no] == ATA_CMD_ID_ATA) ||
-	    (ctx->last_cmd[ap->port_no] == ATA_CMD_PACKET)))
+	    (ctx->last_cmd[ap->port_no] == ATA_CMD_PACKET) ||
+	    (ctx->last_cmd[ap->port_no] == ATA_CMD_SMART)))
 		xgene_ahci_restart_engine(ap);

 	rc = ahci_qc_issue(qc);
--
1.8.2.1

Re: [PATCH v2] ahci_xgene: Fix the dma state machine lockup for the ATA_CMD_SMART PIO mode command.

[Sergei Shtylyov]

Hello.

On 02/02/2015 02:57 PM, Suman Tripathi wrote:

> This patch addresses the issue with ATA_CMD_SMART pio mode
> command for enumeration and device detection with ATA devices.
> The X-Gene AHCI controller has an errata in which it cannot clear
> the BSY bit after the PIO setup FIS. The dma state machine enters
> CMFatalErrorUpdate state and locks up. It is the same issue as
> in the commit 2a0bdff6b958d1b2523d2754b6cd5e0ea4053016(fix the

    You forgot a space before '('.

> dma state machine lockup for the IDENTIFY DEVICE PIO mode
> command).

    Actually, the summary is "ahci_xgene: fix the dma state machine lockup for 
the IDENTIFY DEVICE PIO mode command.", i.e. yours is missing a prefix.

[...]

> Signed-off-by: Suman Tripathi <stripathi@apm.com>
> Reported-by:   Mark Langsdorf <mlangsdo@redhat.com>

MBR, Sergei