]>
Commit | Line | Data |
---|---|---|
86069fea GKH |
1 | From 0d8957c8a90bbb5d34fab9a304459448a5131e06 Mon Sep 17 00:00:00 2001 |
2 | From: Daniel Vetter <daniel.vetter@ffwll.ch> | |
3 | Date: Tue, 7 Aug 2012 09:54:14 +0200 | |
4 | Subject: drm/i915: correctly order the ring init sequence | |
5 | ||
6 | From: Daniel Vetter <daniel.vetter@ffwll.ch> | |
7 | ||
8 | commit 0d8957c8a90bbb5d34fab9a304459448a5131e06 upstream. | |
9 | ||
10 | We may only start to set up the new register values after having | |
11 | confirmed that the ring is truely off. Otherwise the hw might lose the | |
12 | newly written register values. This is caught later on in the init | |
13 | sequence, when we check whether the register writes have stuck. | |
14 | ||
15 | Reviewed-by: Jani Nikula <jani.nikula@intel.com> | |
16 | Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50522 | |
17 | Tested-by: Yang Guang <guang.a.yang@intel.com> | |
18 | Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> | |
19 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
20 | ||
21 | --- | |
22 | drivers/gpu/drm/i915/intel_ringbuffer.c | 7 +++++-- | |
23 | 1 file changed, 5 insertions(+), 2 deletions(-) | |
24 | ||
25 | --- a/drivers/gpu/drm/i915/intel_ringbuffer.c | |
26 | +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c | |
27 | @@ -150,8 +150,6 @@ static int init_ring_common(struct intel | |
28 | I915_WRITE_HEAD(ring, 0); | |
29 | ring->write_tail(ring, 0); | |
30 | ||
31 | - /* Initialize the ring. */ | |
32 | - I915_WRITE_START(ring, obj->gtt_offset); | |
33 | head = I915_READ_HEAD(ring) & HEAD_ADDR; | |
34 | ||
35 | /* G45 ring initialization fails to reset head to zero */ | |
36 | @@ -177,6 +175,11 @@ static int init_ring_common(struct intel | |
37 | } | |
38 | } | |
39 | ||
40 | + /* Initialize the ring. This must happen _after_ we've cleared the ring | |
41 | + * registers with the above sequence (the readback of the HEAD registers | |
42 | + * also enforces ordering), otherwise the hw might lose the new ring | |
43 | + * register values. */ | |
44 | + I915_WRITE_START(ring, obj->gtt_offset); | |
45 | I915_WRITE_CTL(ring, | |
46 | ((ring->size - PAGE_SIZE) & RING_NR_PAGES) | |
47 | | RING_REPORT_64K | RING_VALID); |