On Sun, 2018-06-03 at 22:09 -0700, Himanshu Madhani wrote:
> This patch prevents driver from setting lower default speed
> of 1 GB/sec, if the switch does not support Get Port Speed
> Capabilities (GPSC) command. Setting this default speed results
> into much lower write performance for large sequential WRITE.
> This patch modifies driver to check for gpsc_supported flags and
> prevents driver from issuing MBC_SET_PORT_PARAM (001Ah) to set
> default speed of 1 GB/sec. If driver does not send this mailbox
> command, firmware assumes maximum supported link speed and will
> operate at the max speed.
> 
> Cc: [email protected]
> Signed-off-by: Himanshu Madhani <[email protected]>
> ---
> Hi Martin, 
> 
> This patch fixes lower write performance for large sequential Writes.
> 
> Please apply this to 4.18-scsi-fixes at your earliest convenience. 
> 
> Thanks,
> Himanshu
> ---
>  drivers/scsi/qla2xxx/qla_init.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
> index 1aa3720ea2ed..b0430a280ce6 100644
> --- a/drivers/scsi/qla2xxx/qla_init.c
> +++ b/drivers/scsi/qla2xxx/qla_init.c
> @@ -5007,7 +5007,8 @@ qla2x00_iidma_fcport(scsi_qla_host_t *vha, fc_port_t 
> *fcport)
>               return;
>  
>       if (fcport->fp_speed == PORT_SPEED_UNKNOWN ||
> -         fcport->fp_speed > ha->link_data_rate)
> +         fcport->fp_speed > ha->link_data_rate ||
> +         !ha->flags.gpsc_supported)
>               return;
>  
>       rval = qla2x00_set_idma_speed(vha, fcport->loop_id, fcport->fp_speed,

Martin, 

This patch fixes the issue Eda found in our test environment.

Reported-by: Eda Zhou <[email protected]>
Reviewed-by: Ewan D. Milne <[email protected]>
Tested-by: Ewan D. Milne <[email protected]>


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