drm/i915: Avoid busy-spinning on VLV_GLTC_PW_STATUS mmio
The busy-spin, as the first stage of intel_wait_for_register(), is currently under suspicion for causing: [ 62.034926] NMI watchdog: Watchdog detected hard LOCKUP on cpu 1 [ 62.034928] Modules linked in: i2c_dev i915 intel_gtt drm_kms_helper prime_numbers [ 62.034932] CPU: 1 PID: 183 Comm: kworker/1:2 Not tainted 4.11.0-rc7+ #471 [ 62.034933] Hardware name: / , BIOS PYBSWCEL.86A.0027.2015.0507.1758 05/07/2015 [ 62.034934] Workqueue: pm pm_runtime_work [ 62.034936] task: ffff880275a04ec0 task.stack: ffffc900002d8000 [ 62.034936] RIP: 0010:__intel_wait_for_register_fw+0x77/0x1a0 [i915] [ 62.034937] RSP: 0018:ffffc900002dbc38 EFLAGS: 00000082 [ 62.034939] RAX: ffffc90003530094 RBX: 0000000000130094 RCX: 0000000000000001 [ 62.034940] RDX: 00000000000000a1 RSI: ffff88027fd15e58 RDI: 0000000000000000 [ 62.034941] RBP: ffffc900002dbc78 R08: 0000000000000002 R09: 0000000000000000 [ 62.034942] R10: ffffc900002dbc18 R11: ffff880276429dd0 R12: ffff8802707c0000 [ 62.034943] R13: 00000000000000a0 R14: 0000000000000000 R15: 00000000fffefc10 [ 62.034945] FS: 0000000000000000(0000) GS:ffff88027fd00000(0000) knlGS:0000000000000000 [ 62.034945] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 62.034947] CR2: 00007ffd3cd98ff8 CR3: 0000000274c19000 CR4: 00000000001006e0 [ 62.034947] Call Trace: [ 62.034948] intel_wait_for_register+0x77/0x140 [i915] [ 62.034949] vlv_suspend_complete+0x23/0x5b0 [i915] [ 62.034950] intel_runtime_suspend+0x16c/0x2a0 [i915] [ 62.034950] pci_pm_runtime_suspend+0x50/0x180 [ 62.034951] ? pci_pm_runtime_resume+0xa0/0xa0 [ 62.034952] __rpm_callback+0xc5/0x210 [ 62.034953] rpm_callback+0x1f/0x80 [ 62.034953] ? pci_pm_runtime_resume+0xa0/0xa0 [ 62.034954] rpm_suspend+0x118/0x580 [ 62.034955] pm_runtime_work+0x64/0x90 [ 62.034956] process_one_work+0x1bb/0x3e0 [ 62.034956] worker_thread+0x46/0x4f0 [ 62.034957] ? __schedule+0x18b/0x610 [ 62.034958] kthread+0xff/0x140 [ 62.034958] ? process_one_work+0x3e0/0x3e0 [ 62.034959] ? kthread_create_on_node+ and related hard lockups in CI for byt and bsw. Note this effectively reverts commits41ce405e68andb273669588("drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()") v2: Convert bool allow into a u32 mask for clarity and repeat the comment on vlv rc6 timing to justify the 3ms timeout used for the wait (Ville) Fixes:41ce405e68("drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()") Fixes:b273669588("drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100718 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Tomi Sarvela <tomi.p.sarvela@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170421135815.11897-1-chris@chris-wilson.co.uk Tested-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
This commit is contained in:
Chris Wilson
parent
546cdbc75b
commit
3dd14c04d7
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@ -2175,6 +2175,20 @@ static void vlv_restore_gunit_s0ix_state(struct drm_i915_private *dev_priv)
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I915_WRITE(VLV_GUNIT_CLOCK_GATE2, s->clock_gate_dis2);
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}
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static int vlv_wait_for_pw_status(struct drm_i915_private *dev_priv,
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u32 mask, u32 val)
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{
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/* The HW does not like us polling for PW_STATUS frequently, so
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* use the sleeping loop rather than risk the busy spin within
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* intel_wait_for_register().
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*
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* Transitioning between RC6 states should be at most 2ms (see
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* valleyview_enable_rps) so use a 3ms timeout.
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*/
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return wait_for((I915_READ_NOTRACE(VLV_GTLC_PW_STATUS) & mask) == val,
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3);
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}
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int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool force_on)
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{
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u32 val;
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@ -2203,8 +2217,9 @@ int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool force_on)
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static int vlv_allow_gt_wake(struct drm_i915_private *dev_priv, bool allow)
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{
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u32 mask;
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u32 val;
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int err = 0;
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int err;
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val = I915_READ(VLV_GTLC_WAKE_CTRL);
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val &= ~VLV_GTLC_ALLOWWAKEREQ;
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@ -2213,45 +2228,32 @@ static int vlv_allow_gt_wake(struct drm_i915_private *dev_priv, bool allow)
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I915_WRITE(VLV_GTLC_WAKE_CTRL, val);
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POSTING_READ(VLV_GTLC_WAKE_CTRL);
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err = intel_wait_for_register(dev_priv,
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VLV_GTLC_PW_STATUS,
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VLV_GTLC_ALLOWWAKEACK,
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allow,
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1);
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mask = VLV_GTLC_ALLOWWAKEACK;
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val = allow ? mask : 0;
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err = vlv_wait_for_pw_status(dev_priv, mask, val);
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if (err)
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DRM_ERROR("timeout disabling GT waking\n");
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return err;
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}
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static int vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
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bool wait_for_on)
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static void vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
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bool wait_for_on)
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{
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u32 mask;
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u32 val;
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int err;
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mask = VLV_GTLC_PW_MEDIA_STATUS_MASK | VLV_GTLC_PW_RENDER_STATUS_MASK;
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val = wait_for_on ? mask : 0;
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if ((I915_READ(VLV_GTLC_PW_STATUS) & mask) == val)
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return 0;
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DRM_DEBUG_KMS("waiting for GT wells to go %s (%08x)\n",
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onoff(wait_for_on),
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I915_READ(VLV_GTLC_PW_STATUS));
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/*
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* RC6 transitioning can be delayed up to 2 msec (see
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* valleyview_enable_rps), use 3 msec for safety.
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*/
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err = intel_wait_for_register(dev_priv,
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VLV_GTLC_PW_STATUS, mask, val,
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3);
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if (err)
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if (vlv_wait_for_pw_status(dev_priv, mask, val))
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DRM_ERROR("timeout waiting for GT wells to go %s\n",
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onoff(wait_for_on));
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return err;
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}
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static void vlv_check_no_gt_access(struct drm_i915_private *dev_priv)
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@ -2272,7 +2274,7 @@ static int vlv_suspend_complete(struct drm_i915_private *dev_priv)
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* Bspec defines the following GT well on flags as debug only, so
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* don't treat them as hard failures.
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*/
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(void)vlv_wait_for_gt_wells(dev_priv, false);
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vlv_wait_for_gt_wells(dev_priv, false);
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mask = VLV_GTLC_RENDER_CTX_EXISTS | VLV_GTLC_MEDIA_CTX_EXISTS;
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WARN_ON((I915_READ(VLV_GTLC_WAKE_CTRL) & mask) != mask);
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