From 39eddb4c3970e9aadbc87b8a7cab7b4fefff077f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Richard=20R=C3=B6jfors?= <richard.rojfors@endian.se> Date: Sun, 18 Jan 2009 21:57:35 -0800 Subject: [PATCH] macb: avoid lockup when TGO during underrun MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In rare cases when an underrun occur, all macb buffers where consumed and the netif_queue was stopped infinitely. This happens then the TGO (transfer ongoing) bit in the TSR is set (and UND). It seems like clening up after the underrun makes the driver and the macb hardware end up in an inconsistent state. The result of this is that in the following calls to macb_tx no TX buffers are released -> the netif_queue was stopped, and never woken up again. The solution is to disable the transmitter, if TGO is set, before clening up after the underrun, and re-enable the transmitter when the cleaning up is done. Signed-off-by: Richard Röjfors <richard.rojfors@endian.se> Signed-off-by: David S. Miller <davem@davemloft.net> --- drivers/net/macb.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/macb.c b/drivers/net/macb.c index a04da4ecaa88..f6c4936e2fa8 100644 --- a/drivers/net/macb.c +++ b/drivers/net/macb.c @@ -321,6 +321,10 @@ static void macb_tx(struct macb *bp) printk(KERN_ERR "%s: TX underrun, resetting buffers\n", bp->dev->name); + /* Transfer ongoing, disable transmitter, to avoid confusion */ + if (status & MACB_BIT(TGO)) + macb_writel(bp, NCR, macb_readl(bp, NCR) & ~MACB_BIT(TE)); + head = bp->tx_head; /*Mark all the buffer as used to avoid sending a lost buffer*/ @@ -343,6 +347,10 @@ static void macb_tx(struct macb *bp) } bp->tx_head = bp->tx_tail = 0; + + /* Enable the transmitter again */ + if (status & MACB_BIT(TGO)) + macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TE)); } if (!(status & MACB_BIT(COMP))) -- GitLab