From 5af9a454769bb5528ba1e5268e5649414ae832bd Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Wed, 17 Feb 2016 14:17:42 +0200 Subject: drm/i915: Add helper to get a display power ref if it was already enabled MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We have many places in the code where we check if a given display power domain is enabled and if so access registers backed by this power domain. We assumed that some modeset lock will prevent the power reference from vanishing in the middle of the HW access, but this assumption doesn't always hold. In such cases we get either the wakeref not held, or an unclaimed register access error message. To fix this in a future-proof way that's independent of other locks wrap any such access with a get_ref_if_enabled()/put_ref() pair. Kudos to Ville and Joonas for the ideas of this new interface. v2: - init the power_domains ptr when declaring it everywhere (Joonas) v3: - don't report the device to be powered if runtime PM is disabled CC: Mika Kuoppala CC: Chris Wilson CC: Joonas Lahtinen CC: Ville Syrjälä Signed-off-by: Imre Deak Reviewed-by: Joonas Lahtinen Link: http://patchwork.freedesktop.org/patch/msgid/1455711462-7442-1-git-send-email-imre.deak@intel.com (cherry picked from commit 09731280028ce03e6a27e1998137f1775a2839f3) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_runtime_pm.c | 100 +++++++++++++++++++++++++++++--- 1 file changed, 91 insertions(+), 9 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_runtime_pm.c') diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index ddbdbffe829a..89dcc99ac3ca 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -1442,6 +1442,22 @@ static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv, chv_set_pipe_power_well(dev_priv, power_well, false); } +static void +__intel_display_power_get_domain(struct drm_i915_private *dev_priv, + enum intel_display_power_domain domain) +{ + struct i915_power_domains *power_domains = &dev_priv->power_domains; + struct i915_power_well *power_well; + int i; + + for_each_power_well(i, power_well, BIT(domain), power_domains) { + if (!power_well->count++) + intel_power_well_enable(dev_priv, power_well); + } + + power_domains->domain_use_count[domain]++; +} + /** * intel_display_power_get - grab a power domain reference * @dev_priv: i915 device instance @@ -1457,24 +1473,53 @@ static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv, void intel_display_power_get(struct drm_i915_private *dev_priv, enum intel_display_power_domain domain) { - struct i915_power_domains *power_domains; - struct i915_power_well *power_well; - int i; + struct i915_power_domains *power_domains = &dev_priv->power_domains; intel_runtime_pm_get(dev_priv); - power_domains = &dev_priv->power_domains; + mutex_lock(&power_domains->lock); + + __intel_display_power_get_domain(dev_priv, domain); + + mutex_unlock(&power_domains->lock); +} + +/** + * intel_display_power_get_if_enabled - grab a reference for an enabled display power domain + * @dev_priv: i915 device instance + * @domain: power domain to reference + * + * This function grabs a power domain reference for @domain and ensures that the + * power domain and all its parents are powered up. Therefore users should only + * grab a reference to the innermost power domain they need. + * + * Any power domain reference obtained by this function must have a symmetric + * call to intel_display_power_put() to release the reference again. + */ +bool intel_display_power_get_if_enabled(struct drm_i915_private *dev_priv, + enum intel_display_power_domain domain) +{ + struct i915_power_domains *power_domains = &dev_priv->power_domains; + bool is_enabled; + + if (!intel_runtime_pm_get_if_in_use(dev_priv)) + return false; mutex_lock(&power_domains->lock); - for_each_power_well(i, power_well, BIT(domain), power_domains) { - if (!power_well->count++) - intel_power_well_enable(dev_priv, power_well); + if (__intel_display_power_is_enabled(dev_priv, domain)) { + __intel_display_power_get_domain(dev_priv, domain); + is_enabled = true; + } else { + is_enabled = false; } - power_domains->domain_use_count[domain]++; - mutex_unlock(&power_domains->lock); + + if (!is_enabled) + intel_runtime_pm_put(dev_priv); + + return is_enabled; } /** @@ -2245,6 +2290,43 @@ void intel_runtime_pm_get(struct drm_i915_private *dev_priv) assert_rpm_wakelock_held(dev_priv); } +/** + * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use + * @dev_priv: i915 device instance + * + * This function grabs a device-level runtime pm reference if the device is + * already in use and ensures that it is powered up. + * + * Any runtime pm reference obtained by this function must have a symmetric + * call to intel_runtime_pm_put() to release the reference again. + */ +bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *dev_priv) +{ + struct drm_device *dev = dev_priv->dev; + struct device *device = &dev->pdev->dev; + int ret; + + if (!IS_ENABLED(CONFIG_PM)) + return true; + + ret = pm_runtime_get_if_in_use(device); + + /* + * In cases runtime PM is disabled by the RPM core and we get an + * -EINVAL return value we are not supposed to call this function, + * since the power state is undefined. This applies atm to the + * late/early system suspend/resume handlers. + */ + WARN_ON_ONCE(ret < 0); + if (ret <= 0) + return false; + + atomic_inc(&dev_priv->pm.wakeref_count); + assert_rpm_wakelock_held(dev_priv); + + return true; +} + /** * intel_runtime_pm_get_noresume - grab a runtime pm reference * @dev_priv: i915 device instance -- cgit v1.2.3 From 9b6f20984c5402af06e13cde64b5fe7c31853d1a Mon Sep 17 00:00:00 2001 From: Patrik Jakobsson Date: Thu, 18 Feb 2016 17:21:11 +0200 Subject: drm/i915/gen9: Check for DC state mismatch The DMC can incorrectly run off and allow DC states on it's own. We don't know the root-cause for this yet but this patch makes it more visible. Reviewed-by: Mika Kuoppala Signed-off-by: Patrik Jakobsson Signed-off-by: Imre Deak Link: http://patchwork.freedesktop.org/patch/msgid/1455808874-22089-2-git-send-email-mika.kuoppala@intel.com (cherry picked from commit 832dba889e27487c3087149f1039acc3feb89003) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/intel_csr.c | 2 ++ drivers/gpu/drm/i915/intel_runtime_pm.c | 8 ++++++++ 3 files changed, 11 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_runtime_pm.c') diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index e7cd311e9fbb..b0847b915545 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -751,6 +751,7 @@ struct intel_csr { uint32_t mmio_count; i915_reg_t mmioaddr[8]; uint32_t mmiodata[8]; + uint32_t dc_state; }; #define DEV_INFO_FOR_EACH_FLAG(func, sep) \ diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c index 9bb63a85997a..647d85e77c2f 100644 --- a/drivers/gpu/drm/i915/intel_csr.c +++ b/drivers/gpu/drm/i915/intel_csr.c @@ -240,6 +240,8 @@ void intel_csr_load_program(struct drm_i915_private *dev_priv) I915_WRITE(dev_priv->csr.mmioaddr[i], dev_priv->csr.mmiodata[i]); } + + dev_priv->csr.dc_state = 0; } static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv, diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 89dcc99ac3ca..19e6ff64ce9d 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -494,10 +494,18 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state) val = I915_READ(DC_STATE_EN); DRM_DEBUG_KMS("Setting DC state from %02x to %02x\n", val & mask, state); + + /* Check if DMC is ignoring our DC state requests */ + if ((val & mask) != dev_priv->csr.dc_state) + DRM_ERROR("DC state mismatch (0x%x -> 0x%x)\n", + dev_priv->csr.dc_state, val & mask); + val &= ~mask; val |= state; I915_WRITE(DC_STATE_EN, val); POSTING_READ(DC_STATE_EN); + + dev_priv->csr.dc_state = val & mask; } void bxt_enable_dc9(struct drm_i915_private *dev_priv) -- cgit v1.2.3 From 9b18572e83bfd5378b3fcff3acf123f7bddf558a Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Thu, 18 Feb 2016 17:58:09 +0200 Subject: drm/i915/gen9: Verify and enforce dc6 state writes It has been observed that sometimes disabling the dc6 fails and dc6 state pops back up, brief moment after disabling. This has to be dmc save/restore timing issue or other bug in the way dc states are handled. Try to work around this issue as we don't have firmware fix yet available. Verify that the value we wrote for the dmc sticks, and also enforce it by rewriting it, if it didn't. v2: Zero rereads on rewrite for extra paranoia (Imre) Testcase: kms_flip/basic-flip-vs-dpms References: https://bugs.freedesktop.org/show_bug.cgi?id=93768 Cc: Patrik Jakobsson Cc: Rodrigo Vivi Cc: Imre Deak Signed-off-by: Mika Kuoppala Reviewed-by: Imre Deak Signed-off-by: Imre Deak Link: http://patchwork.freedesktop.org/patch/msgid/1455811089-27884-1-git-send-email-mika.kuoppala@intel.com (cherry picked from commit 779cb5d3ddd72950ec726f86e38f7575c7fbdd4c) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_runtime_pm.c | 41 +++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_runtime_pm.c') diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 19e6ff64ce9d..678ed3475d7e 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -470,6 +470,43 @@ static void gen9_set_dc_state_debugmask_memory_up( } } +static void gen9_write_dc_state(struct drm_i915_private *dev_priv, + u32 state) +{ + int rewrites = 0; + int rereads = 0; + u32 v; + + I915_WRITE(DC_STATE_EN, state); + + /* It has been observed that disabling the dc6 state sometimes + * doesn't stick and dmc keeps returning old value. Make sure + * the write really sticks enough times and also force rewrite until + * we are confident that state is exactly what we want. + */ + do { + v = I915_READ(DC_STATE_EN); + + if (v != state) { + I915_WRITE(DC_STATE_EN, state); + rewrites++; + rereads = 0; + } else if (rereads++ > 5) { + break; + } + + } while (rewrites < 100); + + if (v != state) + DRM_ERROR("Writing dc state to 0x%x failed, now 0x%x\n", + state, v); + + /* Most of the times we need one retry, avoid spam */ + if (rewrites > 1) + DRM_DEBUG_KMS("Rewrote dc state to 0x%x %d times\n", + state, rewrites); +} + static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state) { uint32_t val; @@ -502,8 +539,8 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state) val &= ~mask; val |= state; - I915_WRITE(DC_STATE_EN, val); - POSTING_READ(DC_STATE_EN); + + gen9_write_dc_state(dev_priv, val); dev_priv->csr.dc_state = val & mask; } -- cgit v1.2.3