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: stable@xxxxxxxxxxxxxxx Signed-off-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx> --- 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, -- 2.12.0
