From 650e1203c11354ba84d69ba445abc0efcfe3890a Mon Sep 17 00:00:00 2001
From: Francisco Jerez <currojerez@riseup.net>
Date: Tue, 26 Feb 2013 02:33:11 +0100
Subject: [PATCH] drm/nouveau: Disable AGP on PowerPC again.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---
drivers/gpu/drm/nouveau/nouveau_agp.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/nouveau/nouveau_agp.c b/drivers/gpu/drm/nouveau/nouveau_agp.c
index d28430cd2ba60..6e7a55f93a852 100644
--- a/drivers/gpu/drm/nouveau/nouveau_agp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_agp.c
@@ -47,6 +47,18 @@ nouveau_agp_enabled(struct nouveau_drm *drm)
if (drm->agp.stat == UNKNOWN) {
if (!nouveau_agpmode)
return false;
+#ifdef __powerpc__
+ /* Disable AGP by default on all PowerPC machines for
+ * now -- At least some UniNorth-2 AGP bridges are
+ * known to be broken: DMA from the host to the card
+ * works just fine, but writeback from the card to the
+ * host goes straight to memory untranslated bypassing
+ * the GATT somehow, making them quite painful to deal
+ * with...
+ */
+ if (nouveau_agpmode == -1)
+ return false;
+#endif
return true;
}
--
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