kern/61448: [patch] RealTek driver rl(4) fails to adjust TXthreshold on TX underrun

[Andrew Belashov]

The following reply was made to PR kern/61448; it has been noted by GNATS.

From: Andrew Belashov <bel at orel.ru>
To: freebsd-gnats-submit at FreeBSD.org, tim at eudaemon.net,
	wpaul at FreeBSD.org
Cc:  
Subject: Re: kern/61448: [patch] RealTek driver rl(4) fails to adjust TX threshold
 on TX underrun
Date: Mon, 18 Oct 2004 15:37:07 +0400

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 I have same problem with cardbus PCMCIA card.
 
 Hardware: Fujitsu FMV-BIBLIO NU13 notebook (Pentium I, 133MHz);
 TRENDnet TE100-PCBUSR Cardbus Ethernet card based on RealTek 8139 chip.
 
 Network card is locked by transfer files through ftp or scp.
 Strange messages on console:
 
 ---[dmesg]---
 rl0: discard oversize frame (ether type 6269 flags 3 len 25696 > max 1514)
 rl0: discard oversize frame (ether type 3423 flags 3 len 12589 > max 1514)
 rl0: discard oversize frame (ether type 2f62 flags 3 len 25387 > max 1514)
 ---[dmesg]---
 
 I have added some debug code (thanks ktr(4)) into if_rl.c. For example
 see: <http://www.orel.ru/~bel/patches/if_rl_debug.patch>. This patch also
 resolve my problem.
 
 I offer adapted patch for -CURRENT. See attachment.
 
 With attached patch I do not have any error or problem on my slow notebook.
 Now FTP transfer rate from 1,6 MByte/s to 2,7 MByte/s in any direction.
 
 Note: I do not known how to test patched driver for error recovery from
 RL_TXSTAT_TXABRT or RL_TXSTAT_OUTOFWIN error state.
 
 --
 Best regards,
 Andrew Belashov.
 
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 --- sys/pci/if_rl.c.orig	Thu Sep  9 14:39:52 2004
 +++ sys/pci/if_rl.c	Sun Oct 17 21:49:44 2004
 @@ -1226,31 +1226,33 @@ rl_txeof(struct rl_softc *sc)
  		    RL_TXSTAT_TX_UNDERRUN|RL_TXSTAT_TXABRT)))
  			break;
  
 -		ifp->if_collisions += (txstat & RL_TXSTAT_COLLCNT) >> 24;
 -
  		bus_dmamap_unload(sc->rl_tag, RL_LAST_DMAMAP(sc));
  		bus_dmamap_destroy(sc->rl_tag, RL_LAST_DMAMAP(sc));
  		m_freem(RL_LAST_TXMBUF(sc));
  		RL_LAST_TXMBUF(sc) = NULL;
 -		if (txstat & RL_TXSTAT_TX_OK)
 -			ifp->if_opackets++;
 -		else {
 -			int			oldthresh;
 +		if (txstat & (RL_TXSTAT_OUTOFWIN | RL_TXSTAT_TXABRT)) {
  			ifp->if_oerrors++;
 -			if ((txstat & RL_TXSTAT_TXABRT) ||
 -			    (txstat & RL_TXSTAT_OUTOFWIN))
 -				CSR_WRITE_4(sc, RL_TXCFG, RL_TXCFG_CONFIG);
 -			oldthresh = sc->rl_txthresh;
 -			/* error recovery */
 -			rl_reset(sc);
 -			rl_init_locked(sc);
 +
 +			/* If abort-condition, clear the abort */
 +			if (txstat & RL_TXSTAT_TXABRT) {
 +		 		CSR_WRITE_4(sc, RL_TXCFG, RL_TXCFG_CLRABRT);
 +			}
 +		} else {
 +			ifp->if_opackets++;
 +
  			/*
 -			 * If there was a transmit underrun,
 -			 * bump the TX threshold.
 +			 * Update the RX threshold if underrun is reported.
 +			 * Datasheet says threshold must be between 000001 and
 +			 * 111111 inclusive.  We start at 000011 (96).
  			 */
 -			if (txstat & RL_TXSTAT_TX_UNDERRUN)
 -				sc->rl_txthresh = oldthresh + 32;
 -			return;
 +			if ((txstat & RL_TXSTAT_TX_UNDERRUN) &&
 +			    (sc->rl_txthresh < 2016)) {
 +				sc->rl_txthresh += 64;
 +			}
 +
 +			/* Update collision count, if any */
 +			ifp->if_collisions +=
 +			    (txstat & RL_TXSTAT_COLLCNT) >> 24;
  		}
  		RL_INC(sc->rl_cdata.last_tx);
  		ifp->if_flags &= ~IFF_OACTIVE;
 
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