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authorRichard Röjfors <richard.rojfors@endian.se>2009-01-19 00:57:35 -0500
committerDavid S. Miller <davem@davemloft.net>2009-01-19 19:20:16 -0500
commit39eddb4c3970e9aadbc87b8a7cab7b4fefff077f (patch)
tree840836c811ba0b518be07ff92c1d331e16c94212 /drivers/net
parent24e94de41e76134fad05552588fe01af2cab1494 (diff)
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 <richard.rojfors@endian.se> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/macb.c8
1 files changed, 8 insertions, 0 deletions
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)
321 printk(KERN_ERR "%s: TX underrun, resetting buffers\n", 321 printk(KERN_ERR "%s: TX underrun, resetting buffers\n",
322 bp->dev->name); 322 bp->dev->name);
323 323
324 /* Transfer ongoing, disable transmitter, to avoid confusion */
325 if (status & MACB_BIT(TGO))
326 macb_writel(bp, NCR, macb_readl(bp, NCR) & ~MACB_BIT(TE));
327
324 head = bp->tx_head; 328 head = bp->tx_head;
325 329
326 /*Mark all the buffer as used to avoid sending a lost buffer*/ 330 /*Mark all the buffer as used to avoid sending a lost buffer*/
@@ -343,6 +347,10 @@ static void macb_tx(struct macb *bp)
343 } 347 }
344 348
345 bp->tx_head = bp->tx_tail = 0; 349 bp->tx_head = bp->tx_tail = 0;
350
351 /* Enable the transmitter again */
352 if (status & MACB_BIT(TGO))
353 macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TE));
346 } 354 }
347 355
348 if (!(status & MACB_BIT(COMP))) 356 if (!(status & MACB_BIT(COMP)))