[ 3.5.y.z extended stable ] Patch "b43: Increase number of RX DMA slots" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Tue Feb 26 16:14:45 UTC 2013

This is a note to let you know that I have just added a patch titled

    b43: Increase number of RX DMA slots

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



>From dc066077e97461882ebffb72a36f30b87f7f4242 Mon Sep 17 00:00:00 2001
From: Larry Finger <Larry.Finger at lwfinger.net>
Date: Sun, 17 Feb 2013 17:01:20 +0000
Subject: [PATCH] b43: Increase number of RX DMA slots

commit ccae0e50c16a7f7adb029c169147400d1ce9f703 upstream.

Bastian Bittorf reported that some of the silent freezes on a Linksys WRT54G
were due to overflow of the RX DMA ring buffer, which was created with 64
slots. That finding reminded me that I was seeing similar crashed on a netbook,
which also has a relatively slow processor. After increasing the number of
slots to 128, runs on the netbook that previously failed now worked; however,
I found that 109 slots had been used in one test. For that reason, the number
of slots is being increased to 256.

Signed-off-by: Larry Finger <Larry.Finger at lwfinger.net>
Cc: Bastian Bittorf <bittorf at bluebottle.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 drivers/net/wireless/b43/dma.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/b43/dma.h b/drivers/net/wireless/b43/dma.h
index 315b96e..9fdd198 100644
--- a/drivers/net/wireless/b43/dma.h
+++ b/drivers/net/wireless/b43/dma.h
@@ -169,7 +169,7 @@ struct b43_dmadesc_generic {

 /* DMA engine tuning knobs */
 #define B43_TXRING_SLOTS		256
-#define B43_RXRING_SLOTS		64
+#define B43_RXRING_SLOTS		256
 #define B43_DMA0_RX_FW598_BUFSIZE	(B43_DMA0_RX_FW598_FO + IEEE80211_MAX_FRAME_LEN)
 #define B43_DMA0_RX_FW351_BUFSIZE	(B43_DMA0_RX_FW351_FO + IEEE80211_MAX_FRAME_LEN)


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