From 91355834646328e7edc6bd25176ae44bcd7386c7 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 4 Mar 2011 19:22:40 +0000 Subject: drm/i915: Do not overflow the MMADDR write FIFO Whilst the GT is powered down (rc6), writes to MMADDR are placed in a FIFO by the System Agent. This is a limited resource, only 64 entries, of which 20 are reserved for Display and PCH writes, and so we must take care not to queue up too many writes. To avoid this, there is counter which we can poll to ensure there are sufficient free entries in the fifo. "Issuing a write to a full FIFO is not supported; at worst it could result in corruption or a system hang." Reported-and-Tested-by: Matt Turner Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34056 Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_drv.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/i915_drv.c') diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 0ad533f06af..37d672a116d 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -254,7 +254,7 @@ void intel_detect_pch (struct drm_device *dev) } } -void __gen6_force_wake_get(struct drm_i915_private *dev_priv) +void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv) { int count; @@ -270,12 +270,22 @@ void __gen6_force_wake_get(struct drm_i915_private *dev_priv) udelay(10); } -void __gen6_force_wake_put(struct drm_i915_private *dev_priv) +void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) { I915_WRITE_NOTRACE(FORCEWAKE, 0); POSTING_READ(FORCEWAKE); } +void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv) +{ + int loop = 500; + u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + while (fifo < 20 && loop--) { + udelay(10); + fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + } +} + static int i915_drm_freeze(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; -- cgit v1.2.3-70-g09d2 From a1656b9090f7008d2941c314f5a64724bea2ae37 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 4 Mar 2011 18:48:03 +0000 Subject: drm/i915: Disable GPU semaphores by default Andi Kleen narrowed his GPU hangs on his Sugar Bay (SNB desktop) rev 09 down to the use of GPU semaphores, and we already know that they appear broken up to Huron River (mobile) rev 08. (I'm optimistic that disabling GPU semaphores is simply hiding another bug by the latency and side-effects of the additional device interaction it introduces...) However, use of semaphores is a massive performance improvement... Only as long as the system remains stable. Enable at your peril. Reported-by: Andi Kleen Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33921 Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_drv.c | 3 +++ drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/i915_gem_execbuffer.c | 4 ++-- 3 files changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/i915_drv.c') diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 37d672a116d..22ec066adae 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -46,6 +46,9 @@ module_param_named(fbpercrtc, i915_fbpercrtc, int, 0400); unsigned int i915_powersave = 1; module_param_named(powersave, i915_powersave, int, 0600); +unsigned int i915_semaphores = 0; +module_param_named(semaphores, i915_semaphores, int, 0600); + unsigned int i915_enable_rc6 = 0; module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 549c046b4ec..d023b9b33d6 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -956,6 +956,7 @@ extern struct drm_ioctl_desc i915_ioctls[]; extern int i915_max_ioctl; extern unsigned int i915_fbpercrtc; extern unsigned int i915_powersave; +extern unsigned int i915_semaphores; extern unsigned int i915_lvds_downclock; extern unsigned int i915_panel_use_ssc; extern unsigned int i915_enable_rc6; diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index d2f445e825f..50ab1614571 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -772,8 +772,8 @@ i915_gem_execbuffer_sync_rings(struct drm_i915_gem_object *obj, if (from == NULL || to == from) return 0; - /* XXX gpu semaphores are currently causing hard hangs on SNB mobile */ - if (INTEL_INFO(obj->base.dev)->gen < 6 || IS_MOBILE(obj->base.dev)) + /* XXX gpu semaphores are implicated in various hard hangs on SNB */ + if (INTEL_INFO(obj->base.dev)->gen < 6 || !i915_semaphores) return i915_gem_object_wait_rendering(obj, true); idx = intel_ring_sync_index(from, to); -- cgit v1.2.3-70-g09d2