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path: root/drivers/iommu/intel-svm.c
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Diffstat (limited to 'drivers/iommu/intel-svm.c')
-rw-r--r--drivers/iommu/intel-svm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 97a818992d6d..d9939fa9b588 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -524,6 +524,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)
struct intel_svm *svm = NULL;
int head, tail, handled = 0;
+ /* Clear PPR bit before reading head/tail registers, to
+ * ensure that we get a new interrupt if needed. */
+ writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
+
tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
while (head != tail) {