Re: [PATCH] megaraid_sas: Fallback to older scanning if not disks are found

[Lee Duncan <lduncan@suse.com>]

On 01/15/2016 06:13 AM, Hannes Reinecke wrote:
> commit 21c9e160a51383d4cb0b882398534b0c95c0cc3b implemented a
> new driver lookup using the MR_DCMD_LD_LIST_QUERY firmware command.
> However, this command might not work properly on older firmware,
> causing the command to return no drives instead of an error.
> This causes a regression on older firmware as the driver will
> no longer detect any drives.
> This patch checks if MR_DCMD_LD_LIST_QUERY return no drives,
> and falls back to the original method if so.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  drivers/scsi/megaraid/megaraid_sas_base.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index f97ec34..79dff70 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -4107,6 +4107,10 @@ megasas_ld_list_query(struct megasas_instance *instance, u8 query_type)
>  		ret = megasas_issue_polled(instance, cmd);
>  
>  	tgtid_count = le32_to_cpu(ci->count);
> +	if (tgtid_count == 0) {
> +		/* No drives found, try the older LD list DCMD */
> +		ret = 1;
> +	}
>  
>  	if ((ret == 0) && (tgtid_count <= (instance->fw_supported_vd_count))) {
>  		memset(instance->ld_ids, 0xff, MEGASAS_MAX_LD_IDS);
> 

Reviewed-by: Lee Duncan <lduncan@suse.com>