This is a note to let you know that I've just added the patch titled
drm/i915: Fix GT_MODE default value
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
0018-drm-i915-Fix-GT_MODE-default-value.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From e574d421d77efd42519f36f71fb3f49001b57293 Mon Sep 17 00:00:00 2001
From: Ben Widawsky <[email protected]>
Date: Wed, 3 Oct 2012 19:34:24 -0700
Subject: drm/i915: Fix GT_MODE default value
From: Ben Widawsky <[email protected]>
commit f8f2ac9a76b0f80a6763ca316116a7bab8486997 upstream.
I can't even find how I figured this might be needed anymore. But sure
enough, the value I'm reading back on platforms doesn't match what the
docs recommends.
It seemed to fix Chris' GT1 in limited testing as well.
Tested-by: Chris Wilson <[email protected]>
Signed-off-by: Ben Widawsky <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
[bwh: Backported to 3.2: open-code _MASKED_BIT_{ENABLE,DISABLE}]
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Julien Cristau <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_display.c | 5 +++++
2 files changed, 8 insertions(+)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -445,6 +445,9 @@
# define VS_TIMER_DISPATCH (1 << 6)
# define MI_FLUSH_ENABLE (1 << 12)
+#define GEN6_GT_MODE 0x20d0
+#define GEN6_GT_MODE_HI (1 << 9)
+
#define GFX_MODE 0x02520
#define GFX_MODE_GEN7 0x0229c
#define RING_MODE_GEN7(ring) ((ring)->mmio_base+0x29c)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8620,6 +8620,11 @@ static void gen6_init_clock_gating(struc
DISPPLANE_TRICKLE_FEED_DISABLE);
intel_flush_display_plane(dev_priv, pipe);
}
+
+ /* The default value should be 0x200 according to docs, but the two
+ * platforms I checked have a 0 for this. (Maybe BIOS overrides?) */
+ I915_WRITE(GEN6_GT_MODE, 0xffff << 16);
+ I915_WRITE(GEN6_GT_MODE, GEN6_GT_MODE_HI << 16 | GEN6_GT_MODE_HI);
}
static void gen7_setup_fixed_func_scheduler(struct drm_i915_private *dev_priv)
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/0007-drm-i915-Add-wait_for-in-init_ring_common.patch
queue-3.4/0018-drm-i915-Fix-GT_MODE-default-value.patch
queue-3.4/0004-drm-i915-move-NEEDS_FORCE_WAKE-to-i915_drv.c.patch
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