[PATCH v3] ahci_xgene: Fix the dma state machine lockup for the ATA_CMD_SMART PIO mode command.

[Tejun Heo]

On Mon, Feb 02, 2015 at 11:37:19PM +0530, 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 (ahci-xgene:

The right format is 2a0bdff6b958 ("ahci-xgene: fix the dma state
machine lockup for the IDENTIFY DEVICE PIO mode command").

> 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 shown 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 at apm.com>
> Reported-by:   Mark Langsdorf <mlangsdo at redhat.com>

Applied to libata/for-3.19-fixes.

Thanks.

-- 
tejun