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authorFrancois Romieu <romieu@fr.zoreil.com>2007-08-26 20:08:19 +0200
committerFrancois Romieu <romieu@electric-eye.fr.zoreil.com>2007-09-19 21:52:18 +0200
commitd78ae2dcc2acebb9a1048278f47f762c069db75c (patch)
treeef8c8ec2736e5ce567e5c20287bc11dd4d4ed064 /drivers/net/r8169.c
parent65d916d95314566f426cc40ff0f17b754a773b0b (diff)
r8169: workaround against ignored TxPoll writes (8168)
The 8168 ignores the requests to fetch the Tx descriptors when the relevant TxPoll bit is already set. It easily kills the performances of the 8168. David Gundersen has noticed that it is enough to wait for the completion of the DMA transfer (NPQ bit is cleared) before writing the TxPoll register again. The extra IO traffic added by the proposed workaround could be minimalized but it is not a high-priority task. Fix for: http://bugzilla.kernel.org/show_bug.cgi?id=7924 http://bugzilla.kernel.org/show_bug.cgi?id=8688 (http://bugzilla.kernel.org/show_bug.cgi?id=7555 ?) Signed-off-by: Francois Romieu <romieu@fr.zoreil.com> Cc: David Gundersen <gundy@iinet.net.au> Cc: Edward Hsu <edward_hsu@realtek.com.tw>
Diffstat (limited to 'drivers/net/r8169.c')
-rw-r--r--drivers/net/r8169.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index d9bb51bb4b9..c921ec32c23 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -2570,6 +2570,15 @@ static void rtl8169_tx_interrupt(struct net_device *dev,
(TX_BUFFS_AVAIL(tp) >= MAX_SKB_FRAGS)) {
netif_wake_queue(dev);
}
+ /*
+ * 8168 hack: TxPoll requests are lost when the Tx packets are
+ * too close. Let's kick an extra TxPoll request when a burst
+ * of start_xmit activity is detected (if it is not detected,
+ * it is slow enough). -- FR
+ */
+ smp_rmb();
+ if (tp->cur_tx != dirty_tx)
+ RTL_W8(TxPoll, NPQ);
}
}