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From:   Felix Fietkau <nbd@nbd.name>
To:     linux-wireless@vger.kernel.org
Subject: [PATCH 1/5] mt76: set dma-done flag for flushed descriptors
Date:   Mon, 27 Jan 2020 19:17:50 +0100
Message-Id: <20200127181754.2810-1-nbd@nbd.name>
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Sender: linux-wireless-owner@vger.kernel.org
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Avoids a theoretical corner case where the hardware could try to process
a stale descriptor after a watchdog reset

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/dma.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index 9e03a7871ff4..e69329feed78 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -246,7 +246,9 @@ mt76_dma_dequeue(struct mt76_dev *dev, struct mt76_queue *q, bool flush,
 	if (!q->queued)
 		return NULL;
 
-	if (!flush && !(q->desc[idx].ctrl & cpu_to_le32(MT_DMA_CTL_DMA_DONE)))
+	if (flush)
+		q->desc[idx].ctrl |= cpu_to_le32(MT_DMA_CTL_DMA_DONE);
+	else if (!(q->desc[idx].ctrl & cpu_to_le32(MT_DMA_CTL_DMA_DONE)))
 		return NULL;
 
 	q->tail = (q->tail + 1) % q->ndesc;
-- 
2.24.0