Re: [dpdk-users] Detect LSC capability of dpdk ports

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 27 Jun 2016 11:55:46 +0200
John Sucaet <john.sucaet@oneaccess-net.com> wrote:

> Hi,
> 
> How can a dpdk application determine if a port has support for lsc, 
> before trying to configure it?
> 
> Thanks
> 
> John

We ended up adding this patch, which never seemed to be accepted upstream.
From 79060ea428f070f309f577006af43eb4ab74586d Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <shemming@brocade.com>
Date: Tue, 3 Feb 2015 17:14:32 -0800
Subject: [PATCH 1/7] ether: add function to query for link state interrupt

Allow application to query whether link state will work.
This is also part of abstracting dependency on PCI.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/librte_ether/rte_ethdev.c          |   14 ++++++++++++++
 lib/librte_ether/rte_ethdev.h          |   12 ++++++++++++
 lib/librte_ether/rte_ether_version.map |    1 +
 3 files changed, 27 insertions(+)

--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1091,6 +1091,23 @@ rte_eth_dev_start(uint8_t port_id)
 	return 0;
 }
 
+int
+rte_eth_has_link_state(uint8_t port_id)
+{
+	struct rte_eth_dev *dev;
+
+	if (!rte_eth_dev_is_valid_port(port_id)) {
+		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
+		return 0;
+	}
+	dev = &rte_eth_devices[port_id];
+
+	if (!dev->driver || !dev->pci_dev)
+		return 0;
+
+	return (dev->pci_dev->driver->drv_flags & RTE_PCI_DRV_INTR_LSC) != 0;
+}
+
 void
 rte_eth_dev_stop(uint8_t port_id)
 {
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2149,6 +2149,18 @@ extern void rte_eth_link_get_nowait(uint
 				struct rte_eth_link *link);
 
 /**
+ * Test whether device supports link state interrupt mode.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @return
+ *   - (1) if link state interrupt is supported
+ *   - (0) if link state interrupt is not supported
+ */
+extern int
+rte_eth_has_link_state(uint8_t port_id);
+
+/**
  * Retrieve the general I/O statistics of an Ethernet device.
  *
  * @param port_id
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -83,6 +83,7 @@ DPDK_2.2 {
 	rte_eth_dev_wd_timeout_store;
 	rte_eth_dma_zone_reserve;
 	rte_eth_driver_register;
+	rte_eth_has_link_state;
 	rte_eth_led_off;
 	rte_eth_led_on;
 	rte_eth_link;