Author: adrian
Date: Mon Sep 15 19:53:49 2014
New Revision: 271645
URL: http://svnweb.freebsd.org/changeset/base/271645
Log:
Set DROP_EN on each RX queue if transmit flow-control is disabled.
This allows the NIC to drop frames on the receive queue and not
cause the MAC to block on receiving to _any_ queue.
Tested:
igb0@pci0:5:0:0: class=0x020000 card=0x152115d9 chip=0x15218086
rev=0x01 hdr=0x00
vendor = 'Intel Corporation'
device = 'I350 Gigabit Network Connection'
class = network
subclass = ethernet
Discussed with: Eric Joyner <eric.joy...@intel.com>
MFC after: 1 week
Sponsored by: Norse Corp, Inc.
Modified:
head/sys/dev/e1000/if_igb.c
Modified: head/sys/dev/e1000/if_igb.c
==============================================================================
--- head/sys/dev/e1000/if_igb.c Mon Sep 15 19:48:27 2014 (r271644)
+++ head/sys/dev/e1000/if_igb.c Mon Sep 15 19:53:49 2014 (r271645)
@@ -4712,6 +4712,18 @@ igb_initialize_receive_units(struct adap
rctl |= E1000_RCTL_SZ_2048;
}
+ /*
+ * If TX flow control is disabled and there's >1 queue defined,
+ * enable DROP.
+ *
+ * This drops frames rather than hanging the RX MAC for all queues.
+ */
+ if ((adapter->num_queues > 1) &&
+ (adapter->fc == e1000_fc_none ||
+ adapter->fc == e1000_fc_rx_pause)) {
+ srrctl |= E1000_SRRCTL_DROP_EN;
+ }
+
/* Setup the Base and Length of the Rx Descriptor Rings */
for (int i = 0; i < adapter->num_queues; i++, rxr++) {
u64 bus_addr = rxr->rxdma.dma_paddr;
@@ -6255,6 +6267,7 @@ igb_set_flowcntl(SYSCTL_HANDLER_ARGS)
adapter->hw.fc.current_mode = adapter->hw.fc.requested_mode;
e1000_force_mac_fc(&adapter->hw);
+ /* XXX TODO: update DROP_EN on each RX queue if appropriate */
return (error);
}
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