[kernel] Add patch to fix radeon issues on powerpc

[Josh Boyer]

commit 6f1d3b1ba68513a6d4377dd5723f3942f1b056e3
Author: Josh Boyer <jwboyer at redhat.com>
Date:   Mon Jun 17 10:11:18 2013 -0400

    Add patch to fix radeon issues on powerpc

 ...adeon-Disable-writeback-by-default-on-ppc.patch |   85 ++++++++++++++++++++
 kernel.spec                                        |    9 ++-
 2 files changed, 93 insertions(+), 1 deletions(-)
---
diff --git a/drm-radeon-Disable-writeback-by-default-on-ppc.patch b/drm-radeon-Disable-writeback-by-default-on-ppc.patch
new file mode 100644
index 0000000..0defb13
--- /dev/null
+++ b/drm-radeon-Disable-writeback-by-default-on-ppc.patch
@@ -0,0 +1,85 @@
+From b67e0a6a7409f9c1a12e573fb7d8d80ee455b103 Mon Sep 17 00:00:00 2001
+From: Adam Jackson <ajax at redhat.com>
+Date: Mon, 17 Jun 2013 09:59:34 -0400
+Subject: [PATCH] drm/radeon: Disable writeback by default on ppc
+
+At least on an IBM Power 720, this check passes, but several piglit
+tests will reliably trigger GPU resets due to the ring buffer pointers
+not being updated.  There's probably a better way to limit this to just
+affected machines though.
+
+Signed-off-by: Adam Jackson <ajax at redhat.com>
+---
+ drivers/gpu/drm/radeon/r600_cp.c       | 7 +++++++
+ drivers/gpu/drm/radeon/radeon_cp.c     | 7 +++++++
+ drivers/gpu/drm/radeon/radeon_device.c | 4 ++--
+ drivers/gpu/drm/radeon/radeon_drv.c    | 2 +-
+ 4 files changed, 17 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/gpu/drm/radeon/r600_cp.c b/drivers/gpu/drm/radeon/r600_cp.c
+index 1c51c08..ef28532 100644
+--- a/drivers/gpu/drm/radeon/r600_cp.c
++++ b/drivers/gpu/drm/radeon/r600_cp.c
+@@ -552,6 +552,13 @@ static void r600_test_writeback(drm_radeon_private_t *dev_priv)
+ 		dev_priv->writeback_works = 0;
+ 		DRM_INFO("writeback test failed\n");
+ 	}
++#if defined(__ppc__) || defined(__ppc64__)
++	/* the test might succeed on ppc, but it's usually not reliable */
++	if (radeon_no_wb == -1) {
++		radeon_no_wb = 1;
++		DRM_INFO("not trusting writeback test due to arch quirk\n");
++	}
++#endif
+ 	if (radeon_no_wb == 1) {
+ 		dev_priv->writeback_works = 0;
+ 		DRM_INFO("writeback forced off\n");
+diff --git a/drivers/gpu/drm/radeon/radeon_cp.c b/drivers/gpu/drm/radeon/radeon_cp.c
+index efc4f64..a967b33 100644
+--- a/drivers/gpu/drm/radeon/radeon_cp.c
++++ b/drivers/gpu/drm/radeon/radeon_cp.c
+@@ -892,6 +892,13 @@ static void radeon_test_writeback(drm_radeon_private_t * dev_priv)
+ 		dev_priv->writeback_works = 0;
+ 		DRM_INFO("writeback test failed\n");
+ 	}
++#if defined(__ppc__) || defined(__ppc64__)
++	/* the test might succeed on ppc, but it's usually not reliable */
++	if (radeon_no_wb == -1) {
++		radeon_no_wb = 1;
++		DRM_INFO("not trusting writeback test due to arch quirk\n");
++	}
++#endif
+ 	if (radeon_no_wb == 1) {
+ 		dev_priv->writeback_works = 0;
+ 		DRM_INFO("writeback forced off\n");
+diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
+index 1899738..524046e 100644
+--- a/drivers/gpu/drm/radeon/radeon_device.c
++++ b/drivers/gpu/drm/radeon/radeon_device.c
+@@ -322,8 +322,8 @@ int radeon_wb_init(struct radeon_device *rdev)
+ 	/* disable event_write fences */
+ 	rdev->wb.use_event = false;
+ 	/* disabled via module param */
+-	if (radeon_no_wb == 1) {
+-		rdev->wb.enabled = false;
++	if (radeon_no_wb != -1) {
++		rdev->wb.enabled = !!radeon_no_wb;
+ 	} else {
+ 		if (rdev->flags & RADEON_IS_AGP) {
+ 			/* often unreliable on AGP */
+diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
+index 094e7e5..04809d4 100644
+--- a/drivers/gpu/drm/radeon/radeon_drv.c
++++ b/drivers/gpu/drm/radeon/radeon_drv.c
+@@ -146,7 +146,7 @@ static inline void radeon_register_atpx_handler(void) {}
+ static inline void radeon_unregister_atpx_handler(void) {}
+ #endif
+ 
+-int radeon_no_wb;
++int radeon_no_wb = -1;
+ int radeon_modeset = -1;
+ int radeon_dynclks = -1;
+ int radeon_r4xx_atom = 0;
+-- 
+1.8.2.1
+
diff --git a/kernel.spec b/kernel.spec
index 3986374..d626a89 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -62,7 +62,7 @@ Summary: The Linux kernel
 # For non-released -rc kernels, this will be appended after the rcX and
 # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
 #
-%global baserelease 1
+%global baserelease 2
 %global fedora_build %{baserelease}
 
 # base_sublevel is the kernel version we're starting with and patching
@@ -780,6 +780,8 @@ Patch25045: rt2800-fix-RT5390-RT3290-TX-power-settings-regression.patch
 #rhbz 969644
 Patch25046: KVM-x86-handle-idiv-overflow-at-kvm_write_tsc.patch
 
+Patch25047: drm-radeon-Disable-writeback-by-default-on-ppc.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -1488,6 +1490,8 @@ ApplyPatch rt2800-fix-RT5390-RT3290-TX-power-settings-regression.patch
 #rhbz 969644
 ApplyPatch KVM-x86-handle-idiv-overflow-at-kvm_write_tsc.patch
 
+ApplyPatch drm-radeon-Disable-writeback-by-default-on-ppc.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -2284,6 +2288,9 @@ fi
 #                 ||----w |
 #                 ||     ||
 %changelog
+* Mon Jun 17 2013 Josh Boyer <jwboyer at redhat.com>
+- Add patch to fix radeon issues on powerpc
+
 * Mon Jun 17 2013 Josh Boyer <jwboyer at redhat.com> - 3.10.0-0.rc6.git0.1
 - Linux v3.10-rc6