From 1f8ae0a21d83f43006d7f6d2862e921dbf2eeddd Mon Sep 17 00:00:00 2001 From: Tomasz Lemiech Date: Fri, 13 Mar 2009 15:43:38 -0700 Subject: tulip: Fix for MTU problems with 802.1q tagged frames The original patch was submitted last year but wasn't discussed or applied because of missing maintainer's CCs. I only fixed some formatting errors, but as I saw tulip is very badly formatted and needs further work. Original description: This patch fixes MTU problem, which occurs when using 802.1q VLANs. We should allow receiving frames of up to 1518 bytes in length, instead of 1514. Based on patch written by Ben McKeegan for 2.4.x kernels. It is archived at http://www.candelatech.com/~greear/vlan/howto.html#tulip I've adjusted a few things to make it apply on 2.6.x kernels. Tested on D-Link DFE-570TX quad-fastethernet card. Signed-off-by: Tomasz Lemiech Signed-off-by: Ivan Vecera Signed-off-by: Ben McKeegan Acked-by: Grant Grundler Signed-off-by: David S. Miller --- drivers/net/tulip/tulip.h | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) (limited to 'drivers/net/tulip/tulip.h') diff --git a/drivers/net/tulip/tulip.h b/drivers/net/tulip/tulip.h index 19abbc36b60a..0afa2d4f9472 100644 --- a/drivers/net/tulip/tulip.h +++ b/drivers/net/tulip/tulip.h @@ -201,8 +201,38 @@ enum desc_status_bits { DescStartPkt = 0x20000000, DescEndRing = 0x02000000, DescUseLink = 0x01000000, - RxDescFatalErr = 0x008000, + + /* + * Error summary flag is logical or of 'CRC Error', 'Collision Seen', + * 'Frame Too Long', 'Runt' and 'Descriptor Error' flags generated + * within tulip chip. + */ + RxDescErrorSummary = 0x8000, + RxDescCRCError = 0x0002, + RxDescCollisionSeen = 0x0040, + + /* + * 'Frame Too Long' flag is set if packet length including CRC exceeds + * 1518. However, a full sized VLAN tagged frame is 1522 bytes + * including CRC. + * + * The tulip chip does not block oversized frames, and if this flag is + * set on a receive descriptor it does not indicate the frame has been + * truncated. The receive descriptor also includes the actual length. + * Therefore we can safety ignore this flag and check the length + * ourselves. + */ + RxDescFrameTooLong = 0x0080, + RxDescRunt = 0x0800, + RxDescDescErr = 0x4000, RxWholePkt = 0x00000300, + /* + * Top three bits of 14 bit frame length (status bits 27-29) should + * never be set as that would make frame over 2047 bytes. The Receive + * Watchdog flag (bit 4) may indicate the length is over 2048 and the + * length field is invalid. + */ + RxLengthOver2047 = 0x38000010 }; -- cgit v1.2.3-59-g8ed1b