Hello.
Alan Stern wrote:
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index b626283..e2ecf36 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -421,30 +421,21 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
/*
* Some systems need to revert to PIO when DMA is temporarily
* unavailable. For their sakes, both transfer_buffer and
- * transfer_dma are set when possible. However this can only
- * work on systems without:
+ * transfer_dma are set when possible.
*
- * - HIGHMEM, since DMA buffers located in high memory are
- * not directly addressable by the CPU for PIO;
- *
- * - IOMMU, since dma_map_sg() is allowed to use an IOMMU to
- * make virtually discontiguous buffers be "dma-contiguous"
- * so that PIO and DMA need diferent numbers of URBs.
- *
- * So when HIGHMEM or IOMMU are in use, transfer_buffer is NULL
- * to prevent stale pointers and to help spot bugs.
+ * Note that if the IOMMU coalescing occured, we cannot
s/if the/if/
s/occured/occurred/
Is "occurred" a correct English even? Anyway, "occured"certainly is.
WBR, Sergei
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