Re: [Intel-gfx] [PATCH] drm/i915: Avoid busy-spinning on VLV_GLTC_PW_STATUS mmio
On Fri, Apr 21, 2017 at 02:00:40PM +0100, Chris Wilson wrote:
> 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: 880275a04ec0 task.stack: c92d8000
> [ 62.034936] RIP: 0010:__intel_wait_for_register_fw+0x77/0x1a0 [i915]
> [ 62.034937] RSP: 0018:c92dbc38 EFLAGS: 0082
> [ 62.034939] RAX: c90003530094 RBX: 00130094 RCX:
> 0001
> [ 62.034940] RDX: 00a1 RSI: 88027fd15e58 RDI:
>
> [ 62.034941] RBP: c92dbc78 R08: 0002 R09:
>
> [ 62.034942] R10: c92dbc18 R11: 880276429dd0 R12:
> 8802707c
> [ 62.034943] R13: 00a0 R14: R15:
> fffefc10
> [ 62.034945] FS: () GS:88027fd0()
> knlGS:
> [ 62.034945] CS: 0010 DS: ES: CR0: 80050033
> [ 62.034947] CR2: 7ffd3cd98ff8 CR3: 000274c19000 CR4:
> 001006e0
> [ 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 commits 41ce405e6894 and b27366958869
> ("drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()")
>
> Fixes: 41ce405e6894 ("drm/i915: Convert wait_for(I915_READ(reg)) to
> intel_wait_for_register()")
> Fixes: b27366958869 ("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
> Cc: Tvrtko Ursulin
> Cc: Ville Syrjälä
> Cc: Tomi Sarvela
> ---
> drivers/gpu/drm/i915/i915_drv.c | 39 +--
> 1 file changed, 17 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index e4f902f61e57..89b517c478e8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -2179,6 +2179,17 @@ static void vlv_restore_gunit_s0ix_state(struct
> drm_i915_private *dev_priv)
> I915_WRITE(VLV_GUNIT_CLOCK_GATE2, s->clock_gate_dis2);
> }
>
> +static int vlv_wait_for_pw_status(struct drm_i915_private *dev_priv,
> + u32 mask, u32 val)
> +{
> + /* The HW does not like us polling for PW_STATUS frequently, so
> + * use the sleeping loop rather than risk the busy spin within
> + * intel_wait_for_register().
> + */
> + return wait_for((I915_READ_NOTRACE(VLV_GTLC_PW_STATUS) & mask) == val,
> + 3);
> +}
> +
> int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool force_on)
> {
> u32 val;
> @@ -2208,7 +2219,7 @@ int vlv_force_gfx_clock(struct drm_i915_private
> *dev_priv, bool force_on)
> static int vlv_allow_gt_wake(struct drm_i915_private *dev_priv, bool allow)
> {
> u32 val;
> - int err = 0;
> + int err;
>
> val = I915_READ(VLV_GTLC_WAKE_CTRL);
> val &= ~VLV_GTLC_ALLOWWAKEREQ;
> @@ -2217,45 +2228,29 @@ static int vlv_allow_gt_wake(struct drm_i915_private
> *dev_priv, bool allow)
> I915_WRITE(VLV_GTLC_WAKE_CTRL, val);
> POSTING_READ(VLV_GTLC_WAKE_CTRL);
>
> - err = intel_wait_for_register(dev_priv,
> - VLV_GTLC_PW_STATUS,
> - VLV_GTLC_ALLOWWAKEACK,
> - allow,
> - 1);
> + err = vlv_wait_for_pw_status(dev_priv, VLV_GTLC_ALLOWWAKEACK, allow);
Looks a bit funny to wait for a boolean. Maybe 'allow ? VLV_GTLC_ALLOWWAKEACK :
0'
to make this a little less confusing?
> if (err)
>
[Intel-gfx] [PATCH] 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: 880275a04ec0 task.stack: c92d8000
[ 62.034936] RIP: 0010:__intel_wait_for_register_fw+0x77/0x1a0 [i915]
[ 62.034937] RSP: 0018:c92dbc38 EFLAGS: 0082
[ 62.034939] RAX: c90003530094 RBX: 00130094 RCX: 0001
[ 62.034940] RDX: 00a1 RSI: 88027fd15e58 RDI:
[ 62.034941] RBP: c92dbc78 R08: 0002 R09:
[ 62.034942] R10: c92dbc18 R11: 880276429dd0 R12: 8802707c
[ 62.034943] R13: 00a0 R14: R15: fffefc10
[ 62.034945] FS: () GS:88027fd0()
knlGS:
[ 62.034945] CS: 0010 DS: ES: CR0: 80050033
[ 62.034947] CR2: 7ffd3cd98ff8 CR3: 000274c19000 CR4: 001006e0
[ 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 commits 41ce405e6894 and b27366958869
("drm/i915: Convert wait_for(I915_READ(reg)) to intel_wait_for_register()")
Fixes: 41ce405e6894 ("drm/i915: Convert wait_for(I915_READ(reg)) to
intel_wait_for_register()")
Fixes: b27366958869 ("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
Cc: Tvrtko Ursulin
Cc: Ville Syrjälä
Cc: Tomi Sarvela
---
drivers/gpu/drm/i915/i915_drv.c | 39 +--
1 file changed, 17 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e4f902f61e57..89b517c478e8 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -2179,6 +2179,17 @@ static void vlv_restore_gunit_s0ix_state(struct
drm_i915_private *dev_priv)
I915_WRITE(VLV_GUNIT_CLOCK_GATE2, s->clock_gate_dis2);
}
+static int vlv_wait_for_pw_status(struct drm_i915_private *dev_priv,
+ u32 mask, u32 val)
+{
+ /* The HW does not like us polling for PW_STATUS frequently, so
+* use the sleeping loop rather than risk the busy spin within
+* intel_wait_for_register().
+*/
+ return wait_for((I915_READ_NOTRACE(VLV_GTLC_PW_STATUS) & mask) == val,
+ 3);
+}
+
int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool force_on)
{
u32 val;
@@ -2208,7 +2219,7 @@ int vlv_force_gfx_clock(struct drm_i915_private
*dev_priv, bool force_on)
static int vlv_allow_gt_wake(struct drm_i915_private *dev_priv, bool allow)
{
u32 val;
- int err = 0;
+ int err;
val = I915_READ(VLV_GTLC_WAKE_CTRL);
val &= ~VLV_GTLC_ALLOWWAKEREQ;
@@ -2217,45 +2228,29 @@ static int vlv_allow_gt_wake(struct drm_i915_private
*dev_priv, bool allow)
I915_WRITE(VLV_GTLC_WAKE_CTRL, val);
POSTING_READ(VLV_GTLC_WAKE_CTRL);
- err = intel_wait_for_register(dev_priv,
- VLV_GTLC_PW_STATUS,
- VLV_GTLC_ALLOWWAKEACK,
- allow,
- 1);
+ err = vlv_wait_for_pw_status(dev_priv, VLV_GTLC_ALLOWWAKEACK, allow);
if (err)
DRM_ERROR("timeout disabling GT waking\n");
return err;
}
-static int vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
-bool wait_for_on)
+static void vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
+ bool wait_for_on)
{
u32 mask;
u32 val;
-
