Subject: Re: [e1000]: flow control on by default - good idea really?

From: Auke Kok <[email-masked]>
Date: Tue, 17 Oct 2006 14:02:39 -0700

jamal wrote:
> On Mon, 2006-16-10 at 11:55 -0700, Auke Kok wrote:
>> jamal wrote:
> 
>>> I think when the e1000 says via ethtool "rx is on" - it means that it 
>>> is _advertising_ flow control as opposed to detecting partner has flow
>>> control capability.
>>> Auke, can you also check this as well?
 >>
>> Just found this in my todo box - a bit late :(
>>
>> yes, that appears to be the correct interpretation: we never read back the 
>> detected FC  state from the hardware.

For now, we should really report the FC status in e1000 at link up time. Jamal: this 
should help you out for now, I'll send something like this upstream later on.

Cheers,

Auke

e1000: Display Flow Control setting used after link negotiation

No part of e1000 was reporting which Fc settings were effectively
negotiated with the link partner so that it would be impossible
to know if FC was actually used at all.

Signed-off-by: Auke Kok <[email-masked]>

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index ce0d35f..ff7f396 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -2426,15 +2426,22 @@ e1000_watchdog(unsigned long data)
 
 	if (link) {
 		if (!netif_carrier_ok(netdev)) {
+			uint32_t ctrl;
 			boolean_t txb2b = 1;
 			e1000_get_speed_and_duplex(&adapter->hw,
 			                           &adapter->link_speed,
 			                           &adapter->link_duplex);
 
-			DPRINTK(LINK, INFO, "NIC Link is Up %d Mbps %s\n",
+			ctrl = E1000_READ_REG(&adapter->hw, CTRL);
+			DPRINTK(LINK, INFO, "NIC Link is Up %d Mbps %s, "
+			       "Flow Control: %s\n",
 			       adapter->link_speed,
 			       adapter->link_duplex == FULL_DUPLEX ?
-			       "Full Duplex" : "Half Duplex");
+			       "Full Duplex" : "Half Duplex",
+			       ((ctrl & E1000_CTRL_TFCE) && (ctrl &
+			       E1000_CTRL_RFCE)) ? "RX/TX" : ((ctrl &
+			       E1000_CTRL_RFCE) ? "RX" : ((ctrl &
+			       E1000_CTRL_TFCE) ? "TX" : "None" )));
 
 			/* tweak tx_queue_len according to speed/duplex
 			 * and adjust the timeout factor */