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

[Sergei Shtylyov]

On 02/02/2015 10:37 PM, Suman Tripathi wrote:

    Ugh, please avoid using HTML when posting to the lists hosted on 
vger.kernel.org -- it's configured to ignore such mails AFAIK.

>>>     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

>>     Hum, if this happens after every PIO command (PIO setup FISes are not
>> specific to the command, right?), perhaps it would make more sense to record
>> the *protocol* used by the last command?

> No it happens for IDENTIFY DEVICE, ATA_CMD_PACKET and ATA_CMD_SMART commands .
> It is actually the commands associated with a BSY bit clearing.

    I don't understand that -- BSY bit is cleared for *every* command, either 
at the end of it, or along with setting the DRQ bit for PIO data transfer.

>>>     CMFatalErrorUpdate state and locks up. It is the same issue as
>>>     in the commit 2a0bdff6b958d1b2523d2754b6cd5e__0ea4053016 (ahci-xgene:
>>>     fix the dma state machine lockup for the IDENTIFY DEVICE PIO mode
>>>     command).

>> [...]

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

MBR, Sergei