* [PATCH] agp: use DMA API when compiled for Xen as well
@ 2010-11-12 0:04 Jeremy Fitzhardinge
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From: Jeremy Fitzhardinge @ 2010-11-12 0:04 UTC (permalink / raw)
To: Dave Airlie
Cc: Linux Kernel Mailing List, Xen-devel@lists.xensource.com,
Konrad Rzeszutek Wilk
Xen guests need translation between pseudo-physical and real machine
physical addresses when accessing graphics devices, so use the DMA API
in that case too.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 75e0a34..ce63e5c 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -20,8 +20,12 @@
* an Intel IOMMU. So make the correct use of the PCI DMA API contingent
* on the Intel IOMMU support (CONFIG_DMAR).
* Only newer chipsets need to bother with this, of course.
+ *
+ * Xen guests accessing graphics hardware also need proper translation
+ * between pseudo-physical addresses and real machine addresses, which
+ * is also achieved by using the DMA API.
*/
-#ifdef CONFIG_DMAR
+#if defined(CONFIG_DMAR) || defined(CONFIG_XEN)
#define USE_PCI_DMA_API 1
#endif
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2010-11-12 0:04 [PATCH] agp: use DMA API when compiled for Xen as well Jeremy Fitzhardinge
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