Commit d830418e authored Nov 25, 2010 by Yang Li Committed by David S. Miller Nov 28, 2010

ucc_geth: fix ucc halt problem in half duplex mode



In commit 58933c64(ucc_geth: Fix the wrong the Rx/Tx FIFO size),
the UCC_GETH_UTFTT_INIT is set to 512 based on the recommendation
of the QE Reference Manual.  But that will sometimes cause tx halt
while working in half duplex mode.

According to errata draft QE_GENERAL-A003(High Tx Virtual FIFO
threshold size can cause UCC to halt), setting UTFTT less than
[(UTFS x (M - 8)/M) - 128] will prevent this from happening
(M is the minimum buffer size).

The patch changes UTFTT back to 256.

Signed-off-by: Li Yang <leoli@freescale.com>
Cc: Jean-Denis Boyer <jdboyer@media5corp.com>
Cc: Andreas Schmitz <Andreas.Schmitz@riedel.net>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b4ff3c90

drivers/net/ucc_geth.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -899,7 +899,8 @@ struct ucc_geth_hardware_statistics {
		#define UCC_GETH_UTFS_INIT 512 /* Tx virtual FIFO size
		*/
		#define UCC_GETH_UTFET_INIT 256 /* 1/2 utfs */
		#define UCC_GETH_UTFTT_INIT 512
		#define UCC_GETH_UTFTT_INIT 256 /* 1/2 utfs
		due to errata */
		/* Gigabit Ethernet (1000 Mbps) */
		#define UCC_GETH_URFS_GIGA_INIT 4096/2048/ /* Rx virtual
		FIFO size */

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