Gianfar - MPC8541 - tx buffer overrun errors

Gianfar - MPC8541 - tx buffer overrun errors

[Shriram Janardhan]

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All,
   
  I am running 2.6.11 version of the kernel on MPC8541.  Have one of the TSECs configured at 100Mbps/Full Duplex.  The TSEC MAC is connected to a Marvell Ethernet switch MAC without any PHY in between.  MAC level flow control is enabled but no pause frames sent or received.
   
  I see a high number of transmit buffer overrun errors (tx_fifo_empty errors in the gianfar driver).  I don't have NAPI enabled.  In addition to other things, I was thinking of enabling NAPI and see if it helps - is there any downside to it??  Are there any other parameters that I could tweak to reduce/eliminate the overrun errors??
   
  Thanks,
  Shriram.
   

       
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RE: Gianfar - MPC8541 - tx buffer overrun errors

[Joyeau Sylvain]

Hi Shriram,

Try to increase the DEFAULT_TX_RING_SIZE parameter in gianfar.h.
Enabling NAPI mechanism should have no effect on transmission side.

Cheers
--
sj


________________________________

	From:
linuxppc-embedded-bounces+sylvain.joyeau=3Dthomson.net@ozlabs.org
[mailto:linuxppc-embedded-bounces+sylvain.joyeau=3Dthomson.net@ozlabs.org=
]
On Behalf Of Shriram Janardhan
	Sent: jeudi 6 septembre 2007 03:49
	To: linuxppc-embedded@ozlabs.org
	Subject: Gianfar - MPC8541 - tx buffer overrun errors
=09
=09
	All,
	=20
	I am running 2.6.11 version of the kernel on MPC8541.  Have one
of the TSECs configured at 100Mbps/Full Duplex.  The TSEC MAC is
connected to a Marvell Ethernet switch MAC without any PHY in between.
MAC level flow control is enabled but no pause frames sent or received.
	=20
	I see a high number of transmit buffer overrun errors
(tx_fifo_empty errors in the gianfar driver).  I don't have NAPI
enabled.  In addition to other things, I was thinking of enabling NAPI
and see if it helps - is there any downside to it??  Are there any other
parameters that I could tweak to reduce/eliminate the overrun errors??
	=20
	Thanks,
	Shriram.
	=20

	________________________________

	Got a little couch potato?=20
	Check out fun summer activities for kids.
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