From: Richard Röjfors Date: Mon, 19 Jan 2009 05:57:35 +0000 (-0800) Subject: macb: avoid lockup when TGO during underrun X-Git-Tag: v2.6.29-rc3~23^2~63 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=39eddb4c3970e9aadbc87b8a7cab7b4fefff077f;p=linux-2.6-omap-h63xx.git macb: avoid lockup when TGO during underrun 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 Signed-off-by: David S. Miller --- diff --git a/drivers/net/macb.c b/drivers/net/macb.c index a04da4ecaa8..f6c4936e2fa 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)))