From: Francisco Jerez <currojerez@riseup.net>
Date: Tue, 26 Feb 2013 01:33:11 +0000 (+0100)
Subject: drm/nouveau: Disable AGP on PowerPC again.
X-Git-Tag: v3.9-rc2~15^2~7^2~4
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=650e1203c11354ba84d69ba445abc0efcfe3890a;p=linux.git

drm/nouveau: Disable AGP on PowerPC again.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---

diff --git a/drivers/gpu/drm/nouveau/nouveau_agp.c b/drivers/gpu/drm/nouveau/nouveau_agp.c
index d28430cd2ba6..6e7a55f93a85 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;
 	}