From 73b82bf0bfbf58e6ff328d3726934370585f6e78 Mon Sep 17 00:00:00 2001 From: Thommy Jakobsson Date: Tue, 23 Apr 2013 21:45:11 +0200 Subject: B43: Handle DMA RX descriptor underrun Add handling of rx descriptor underflow. This fixes a fault that could happen on slow machines, where data is received faster than the CPU can handle. In such a case the device will use up all rx descriptors and refuse to send any more data before confirming that it is ok. This patch enables necessary interrupt to discover such a situation and will handle them by dropping everything in the ring buffer. Reviewed-by: Michael Buesch Signed-off-by: Thommy Jakobsson Cc: stable Signed-off-by: John W. Linville --- drivers/net/wireless/b43/dma.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers/net/wireless/b43/dma.c') diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c index 122146943bf..ee3d6403c79 100644 --- a/drivers/net/wireless/b43/dma.c +++ b/drivers/net/wireless/b43/dma.c @@ -1733,6 +1733,25 @@ drop_recycle_buffer: sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize); } +void b43_dma_handle_rx_overflow(struct b43_dmaring *ring) +{ + int current_slot, previous_slot; + + B43_WARN_ON(ring->tx); + + /* Device has filled all buffers, drop all packets and let TCP + * decrease speed. + * Decrement RX index by one will let the device to see all slots + * as free again + */ + /* + *TODO: How to increase rx_drop in mac80211? + */ + current_slot = ring->ops->get_current_rxslot(ring); + previous_slot = prev_slot(ring, current_slot); + ring->ops->set_current_rxslot(ring, previous_slot); +} + void b43_dma_rx(struct b43_dmaring *ring) { const struct b43_dma_ops *ops = ring->ops; -- cgit v1.2.3-70-g09d2