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Date:   Mon, 7 Oct 2019 09:34:48 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Arvind Sankar <nivedita@alum.mit.edu>
Cc:     linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: ehci-pci breakage with dma-mapping changes in 5.4-rc2
Message-ID: <20191007073448.GA882@lst.de>
References: <20191007022454.GA5270@rani.riverdale.lan>
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Hi Arvind,

can you try the patch below?


diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 3f974919d3bd..52b709bf2b55 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3775,6 +3775,13 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
 	return nelems;
 }
 
+static u64 intel_get_required_mask(struct device *dev)
+{
+	if (!iommu_need_mapping(dev))
+		return dma_direct_get_required_mask(dev);
+	return DMA_BIT_MASK(32);
+}
+
 static const struct dma_map_ops intel_dma_ops = {
 	.alloc = intel_alloc_coherent,
 	.free = intel_free_coherent,
@@ -3787,6 +3794,7 @@ static const struct dma_map_ops intel_dma_ops = {
 	.dma_supported = dma_direct_supported,
 	.mmap = dma_common_mmap,
 	.get_sgtable = dma_common_get_sgtable,
+	.get_required_mask = intel_get_required_mask,
 };
 
 static void