From b19c399da7b857c8d9fd899a42bee0144e03465a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 11 Feb 2014 19:52:06 +0200 Subject: [PATCH] drm/i915: Prevent MI_DISPLAY_FLIP straddling two cachelines on IVB MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit f66fab8e1cd6b3127ba4c5c0d11539fbe1de1e36 upstream. According to BSpec the entire MI_DISPLAY_FLIP packet must be contained in a single cacheline. Make sure that happens. v2: Use intel_ring_begin_cacheline_safe() v3: Use intel_ring_cacheline_align() (Chris) Cc: Bjoern C Cc: Alexandru DAMIAN Cc: Enrico Tagliavini Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74053 Signed-off-by: Ville Syrjälä Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Signed-off-by: Jiri Slaby --- drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index dd2d542..9dcf34f 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7946,6 +7946,20 @@ static int intel_gen7_queue_flip(struct drm_device *dev, if (ring->id == RCS) len += 6; + /* + * BSpec MI_DISPLAY_FLIP for IVB: + * "The full packet must be contained within the same cache line." + * + * Currently the LRI+SRM+MI_DISPLAY_FLIP all fit within the same + * cacheline, if we ever start emitting more commands before + * the MI_DISPLAY_FLIP we may need to first emit everything else, + * then do the cacheline alignment, and finally emit the + * MI_DISPLAY_FLIP. + */ + ret = intel_ring_cacheline_align(ring); + if (ret) + goto err_unpin; + ret = intel_ring_begin(ring, len); if (ret) goto err_unpin; -- 2.7.4