Re: [PATCH #upstream-fixes] libata: clear ering on resume

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> Error timestamps are in jiffies which doesn't run while suspended and
> PHY events during resume isn't too uncommon.  When the two are
> combined, it can lead to unnecessary speed downs if the machine is
> suspended and resumed repeatedly.  Clear error history on resume.
> 
> This was reported and verified in bnc#486803 by Vladimir Botka.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Reported-by: Vladimir Botka <vbotka@novell.com>
> ---
>  drivers/ata/libata-eh.c |   13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
> index 0183131..ff0f496 100644
> --- a/drivers/ata/libata-eh.c
> +++ b/drivers/ata/libata-eh.c
> @@ -3494,6 +3494,8 @@ static void ata_eh_handle_port_suspend(struct ata_port *ap)
>   */
>  static void ata_eh_handle_port_resume(struct ata_port *ap)
>  {
> +	struct ata_link *link;
> +	struct ata_device *dev;
>  	unsigned long flags;
>  	int rc = 0;
>  
> @@ -3508,6 +3510,17 @@ static void ata_eh_handle_port_resume(struct ata_port *ap)
>  
>  	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
>  
> +	/*
> +	 * Error timestamps are in jiffies which doesn't run while
> +	 * suspended and PHY events during resume isn't too uncommon.
> +	 * When the two are combined, it can lead to unnecessary speed
> +	 * downs if the machine is suspended and resumed repeatedly.
> +	 * Clear error history.
> +	 */
> +	ata_for_each_link(link, ap, HOST_FIRST)
> +		ata_for_each_dev(dev, link, ALL)
> +			ata_ering_clear(&dev->ering);
> +
>  	ata_acpi_set_state(ap, PMSG_ON);

applied