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| author | Hans de Goede <j.w.r.degoede@gmail.com> | 2017-10-19 14:16:20 +0300 |
|---|---|---|
| committer | Hans de Goede <hdegoede@redhat.com> | 2017-11-10 15:14:03 +0300 |
| commit | a5266db4d31410fbfb4f40118e58085994e83dbc (patch) | |
| tree | b099422f48b315d1e9f83da9b80a722dd7fd36ec /drivers/gpu/drm/i915/intel_uncore.c | |
| parent | af0ab55ffe2467fab82bc0909e469cba7701fac7 (diff) | |
| download | linux-a5266db4d31410fbfb4f40118e58085994e83dbc.tar.xz | |
drm/i915: Acquire PUNIT->PMIC bus for intel_uncore_forcewake_reset()
intel_uncore_forcewake_reset() does forcewake puts and gets as such
we need to make sure that no-one tries to access the PUNIT->PMIC bus
(on systems where this bus is shared) while it runs, otherwise bad
things happen.
Normally this is taken care of by the i915_pmic_bus_access_notifier()
which does an intel_uncore_forcewake_get(FORCEWAKE_ALL) when some other
driver tries to access the PMIC bus, so that later forcewake gets are
no-ops (for the duration of the bus access).
But intel_uncore_forcewake_reset gets called in 3 cases:
1) Before registering the pmic_bus_access_notifier
2) After unregistering the pmic_bus_access_notifier
3) To reset forcewake state on a GPU reset
In all 3 cases the i915_pmic_bus_access_notifier() protection is
insufficient.
This commit fixes this race by calling iosf_mbi_punit_acquire() before
calling intel_uncore_forcewake_reset(). In the case where it is called
directly after unregistering the pmic_bus_access_notifier, we need to
hold the punit-lock over both calls to avoid a race where
intel_uncore_fw_release_timer() may execute between the 2 calls.
Reviewed-by: Imre Deak <imre.deak@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171019111620.26761-3-hdegoede@redhat.com
Diffstat (limited to 'drivers/gpu/drm/i915/intel_uncore.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_uncore.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 0a6d952a2df1..211acee7c31d 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -345,6 +345,7 @@ intel_uncore_fw_release_timer(struct hrtimer *timer) return HRTIMER_NORESTART; } +/* Note callers must have acquired the PUNIT->PMIC bus, before calling this. */ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv, bool restore) { @@ -353,6 +354,8 @@ static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv, int retry_count = 100; enum forcewake_domains fw, active_domains; + iosf_mbi_assert_punit_acquired(); + /* Hold uncore.lock across reset to prevent any register access * with forcewake not set correctly. Wait until all pending * timers are run before holding. @@ -532,14 +535,18 @@ static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv, GT_FIFO_CTL_RC6_POLICY_STALL); } + iosf_mbi_punit_acquire(); intel_uncore_forcewake_reset(dev_priv, restore_forcewake); + iosf_mbi_punit_release(); } void intel_uncore_suspend(struct drm_i915_private *dev_priv) { - iosf_mbi_unregister_pmic_bus_access_notifier( + iosf_mbi_punit_acquire(); + iosf_mbi_unregister_pmic_bus_access_notifier_unlocked( &dev_priv->uncore.pmic_bus_access_nb); intel_uncore_forcewake_reset(dev_priv, false); + iosf_mbi_punit_release(); } void intel_uncore_resume_early(struct drm_i915_private *dev_priv) @@ -1419,12 +1426,14 @@ void intel_uncore_init(struct drm_i915_private *dev_priv) void intel_uncore_fini(struct drm_i915_private *dev_priv) { - iosf_mbi_unregister_pmic_bus_access_notifier( - &dev_priv->uncore.pmic_bus_access_nb); - /* Paranoia: make sure we have disabled everything before we exit. */ intel_uncore_sanitize(dev_priv); + + iosf_mbi_punit_acquire(); + iosf_mbi_unregister_pmic_bus_access_notifier_unlocked( + &dev_priv->uncore.pmic_bus_access_nb); intel_uncore_forcewake_reset(dev_priv, false); + iosf_mbi_punit_release(); } static const struct reg_whitelist { |