Re: [PATCH] hpsa: add heartbeat sysfs host attribute

From: Greg KH
Date: Fri Aug 12 2011 - 22:03:49 EST


On Fri, Aug 12, 2011 at 01:03:14PM -0500, Stephen M. Cameron wrote:
> From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
>
> The cciss driver had a CCISS_HEARTBEAT ioctl which
> was not implemented in hpsa. This ioctl returned a
> counter from a register on the Smart Array which the
> firmware would periodically update. It can be used
> to detect certain kinds of faults (e.g. controller
> lockup) by noticing when the value remains constant
> for more than a second or two.
>
> Signed-off-by: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
> ---
> Documentation/scsi/hpsa.txt | 8 ++++++++
> drivers/scsi/hpsa.c | 18 ++++++++++++++++++
> 2 files changed, 26 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/scsi/hpsa.txt b/Documentation/scsi/hpsa.txt
> index 891435a..0dac1e0 100644
> --- a/Documentation/scsi/hpsa.txt
> +++ b/Documentation/scsi/hpsa.txt
> @@ -47,6 +47,7 @@ HPSA specific entries in /sys
> /sys/class/scsi_host/host*/firmware_revision
> /sys/class/scsi_host/host*/resettable
> /sys/class/scsi_host/host*/transport_mode
> + /sys/class/scsi_host/host*/heartbeat
>
> the host "rescan" attribute is a write only attribute. Writing to this
> attribute will cause the driver to scan for new, changed, or removed devices
> @@ -78,6 +79,13 @@ HPSA specific entries in /sys
> kexec tools to warn the user if they attempt to designate a device which is
> unable to honor the reset_devices kernel parameter as a dump device.
>
> + The "heartbeat" read-only attribute returns the value of a heartbeat
> + counter register on a Smart Array controller as a 32 bit unsigned
> + hexadecimal integer (e.g: "0x12345678"). The value should change
> + periodically, not less than once per second. If this value fails to
> + change for a period longer than one second, it means something has
> + gone wrong (e.g. Smart Array controller firmware has locked up.)
> +

This all belongs in Documentation/ABI/ care to move it there instead?

greg k-h
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