Re: [PATCH v2 09/14] drm/i915: Fix edp vdd locking

Imre Deak
2014-09-02T13:09:05Z

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On Tue, 2014-08-19 at 20:32 +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Introduce a new mutex (pps_mutex) to protect the power sequencer
> state. For now this state includes want_panel_vdd as well as the
> power sequencer registers.
>
> We need a single mutex (as opposed to per port) because later on we
> will need to deal with VLV/CHV which have multiple power sequencer
> which can be reassigned to different ports.
>
> v2: Add the locking to intel_dp_encoder_suspend too (Imre)
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 3 ++
> drivers/gpu/drm/i915/intel_display.c | 2 +
> drivers/gpu/drm/i915/intel_dp.c | 99 ++++++++++++++++++++++++++++++++----
> 3 files changed, 93 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 6fbd316..c5faefb 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1501,6 +1501,9 @@ struct drm_i915_private {
> /* LVDS info */
> bool no_aux_handshake;
>
> + /* protects panel power sequencer state */
> + struct mutex pps_mutex;
> +
> struct drm_i915_fence_reg fence_regs[I915_MAX_NUM_FENCES]; /* assume 965 */
> int fence_reg_start; /* 4 if userland hasn't ioctl'd us yet */
> int num_fence_regs; /* 8 on pre-965, 16 otherwise */
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 0b327eb..ff86729 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12437,6 +12437,8 @@ static void intel_init_display(struct drm_device *dev)
> }
>
> intel_panel_init_backlight_funcs(dev);
> +
> + mutex_init(&dev_priv->pps_mutex);
> }
>
> /*
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 9efa6bf..446df28 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -300,6 +300,8 @@ vlv_power_sequencer_pipe(struct intel_dp *intel_dp)
> enum port port = intel_dig_port->port;
> enum pipe pipe;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> /* modeset should have pipe */
> if (crtc)
> return to_intel_crtc(crtc)->pipe;
> @@ -352,6 +354,8 @@ static int edp_notify_handler(struct notifier_block *this, unsigned long code,
> if (!IS_VALLEYVIEW(dev) || !is_edp(intel_dp) || code != SYS_RESTART)
> return 0;
>
> + mutex_lock(&dev_priv->pps_mutex);
> +

This needs rebasing since 02/14 wasn't applied.

> pipe = vlv_power_sequencer_pipe(intel_dp);
>
> pp_ctrl_reg = VLV_PIPE_PP_CONTROL(pipe);
> @@ -364,6 +368,8 @@ static int edp_notify_handler(struct notifier_block *this, unsigned long code,
> I915_WRITE(pp_ctrl_reg, PANEL_UNLOCK_REGS | PANEL_POWER_OFF);
> msleep(intel_dp->panel_power_cycle_delay);
>
> + mutex_unlock(&dev_priv->pps_mutex);
> +
> return 0;
> }
>
> @@ -372,6 +378,8 @@ static bool edp_have_panel_power(struct intel_dp *intel_dp)
> struct drm_device *dev = intel_dp_to_dev(intel_dp);
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> return (I915_READ(_pp_stat_reg(intel_dp)) & PP_ON) != 0;
> }
>
> @@ -383,6 +391,8 @@ static bool edp_have_panel_vdd(struct intel_dp *intel_dp)
> struct intel_encoder *intel_encoder = &intel_dig_port->base;
> enum intel_display_power_domain power_domain;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> power_domain = intel_display_port_power_domain(intel_encoder);
> return intel_display_power_enabled(dev_priv, power_domain) &&
> (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
> @@ -533,6 +543,8 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
> bool has_aux_irq = HAS_AUX_IRQ(dev);
> bool vdd;
>
> + mutex_lock(&dev_priv->pps_mutex);
> +
> /*
> * We will be called with VDD already enabled for dpcd/edid/oui reads.
> * In such cases we want to leave VDD enabled and it's up to upper layers
> @@ -648,6 +660,8 @@ out:
> if (vdd)
> edp_panel_vdd_off(intel_dp, false);
>
> + mutex_unlock(&dev_priv->pps_mutex);
> +
> return ret;
> }
>
> @@ -1102,6 +1116,8 @@ static void wait_panel_status(struct intel_dp *intel_dp,
> struct drm_i915_private *dev_priv = dev->dev_private;
> u32 pp_stat_reg, pp_ctrl_reg;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> pp_stat_reg = _pp_stat_reg(intel_dp);
> pp_ctrl_reg = _pp_ctrl_reg(intel_dp);
>
> @@ -1165,6 +1181,8 @@ static u32 ironlake_get_pp_control(struct intel_dp *intel_dp)
> struct drm_i915_private *dev_priv = dev->dev_private;
> u32 control;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> control = I915_READ(_pp_ctrl_reg(intel_dp));
> control &= ~PANEL_UNLOCK_MASK;
> control |= PANEL_UNLOCK_REGS;
> @@ -1182,6 +1200,8 @@ static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
> u32 pp_stat_reg, pp_ctrl_reg;
> bool need_to_disable = !intel_dp->want_panel_vdd;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> if (!is_edp(intel_dp))
> return false;
>
> @@ -1221,12 +1241,16 @@ static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
>
> void intel_edp_panel_vdd_on(struct intel_dp *intel_dp)
> {
> + struct drm_i915_private *dev_priv =
> + intel_dp_to_dev(intel_dp)->dev_private;
> bool vdd;
>
> if (!is_edp(intel_dp))
> return;
>
> + mutex_lock(&dev_priv->pps_mutex);
> vdd = edp_panel_vdd_on(intel_dp);
> + mutex_unlock(&dev_priv->pps_mutex);
>
> WARN(!vdd, "eDP VDD already requested on\n");
> }
> @@ -1242,7 +1266,7 @@ static void edp_panel_vdd_off_sync(struct intel_dp *intel_dp)
> u32 pp;
> u32 pp_stat_reg, pp_ctrl_reg;
>
> - WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> + lockdep_assert_held(&dev_priv->pps_mutex);
>
> WARN_ON(intel_dp->want_panel_vdd);
>
> @@ -1275,12 +1299,13 @@ static void edp_panel_vdd_work(struct work_struct *__work)
> {
> struct intel_dp *intel_dp = container_of(to_delayed_work(__work),
> struct intel_dp, panel_vdd_work);
> - struct drm_device *dev = intel_dp_to_dev(intel_dp);
> + struct drm_i915_private *dev_priv =
> + intel_dp_to_dev(intel_dp)->dev_private;
>
> - drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> + mutex_lock(&dev_priv->pps_mutex);
> if (!intel_dp->want_panel_vdd)
> edp_panel_vdd_off_sync(intel_dp);
> - drm_modeset_unlock(&dev->mode_config.connection_mutex);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> static void edp_panel_vdd_schedule_off(struct intel_dp *intel_dp)
> @@ -1298,6 +1323,11 @@ static void edp_panel_vdd_schedule_off(struct intel_dp *intel_dp)
>
> static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
> {
> + struct drm_i915_private *dev_priv =
> + intel_dp_to_dev(intel_dp)->dev_private;
> +
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> if (!is_edp(intel_dp))
> return;
>
> @@ -1313,7 +1343,15 @@ static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
>
> static void intel_edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
> {
> + struct drm_i915_private *dev_priv =
> + intel_dp_to_dev(intel_dp)->dev_private;
> +
> + if (!is_edp(intel_dp))
> + return;
> +
> + mutex_lock(&dev_priv->pps_mutex);
> edp_panel_vdd_off(intel_dp, sync);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> void intel_edp_panel_on(struct intel_dp *intel_dp)
> @@ -1328,9 +1366,11 @@ void intel_edp_panel_on(struct intel_dp *intel_dp)
>
> DRM_DEBUG_KMS("Turn eDP power on\n");
>
> + mutex_lock(&dev_priv->pps_mutex);
> +
> if (edp_have_panel_power(intel_dp)) {
> DRM_DEBUG_KMS("eDP power already on\n");
> - return;
> + goto out;
> }
>
> wait_panel_power_cycle(intel_dp);
> @@ -1359,6 +1399,9 @@ void intel_edp_panel_on(struct intel_dp *intel_dp)
> I915_WRITE(pp_ctrl_reg, pp);
> POSTING_READ(pp_ctrl_reg);
> }
> +
> + out:
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> void intel_edp_panel_off(struct intel_dp *intel_dp)
> @@ -1376,6 +1419,8 @@ void intel_edp_panel_off(struct intel_dp *intel_dp)
>
> DRM_DEBUG_KMS("Turn eDP power off\n");
>
> + mutex_lock(&dev_priv->pps_mutex);
> +
> WARN(!intel_dp->want_panel_vdd, "Need VDD to turn off panel\n");
>
> pp = ironlake_get_pp_control(intel_dp);
> @@ -1397,6 +1442,8 @@ void intel_edp_panel_off(struct intel_dp *intel_dp)
> /* We got a reference when we enabled the VDD. */
> power_domain = intel_display_port_power_domain(intel_encoder);
> intel_display_power_put(dev_priv, power_domain);
> +
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> void intel_edp_backlight_on(struct intel_dp *intel_dp)
> @@ -1421,6 +1468,9 @@ void intel_edp_backlight_on(struct intel_dp *intel_dp)
> * allowing it to appear.
> */
> wait_backlight_on(intel_dp);
> +
> + mutex_lock(&dev_priv->pps_mutex);
> +
> pp = ironlake_get_pp_control(intel_dp);
> pp |= EDP_BLC_ENABLE;
>
> @@ -1428,6 +1478,8 @@ void intel_edp_backlight_on(struct intel_dp *intel_dp)
>
> I915_WRITE(pp_ctrl_reg, pp);
> POSTING_READ(pp_ctrl_reg);
> +
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> void intel_edp_backlight_off(struct intel_dp *intel_dp)
> @@ -1440,6 +1492,8 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp)
> if (!is_edp(intel_dp))
> return;
>
> + mutex_lock(&dev_priv->pps_mutex);
> +
> DRM_DEBUG_KMS("\n");
> pp = ironlake_get_pp_control(intel_dp);
> pp &= ~EDP_BLC_ENABLE;
> @@ -1448,8 +1502,10 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp)
>
> I915_WRITE(pp_ctrl_reg, pp);
> POSTING_READ(pp_ctrl_reg);
> - intel_dp->last_backlight_off = jiffies;
>
> + mutex_unlock(&dev_priv->pps_mutex);
> +
> + intel_dp->last_backlight_off = jiffies;
> edp_wait_backlight_off(intel_dp);
>
> intel_panel_disable_backlight(intel_dp->attached_connector);

These need to be rebased on the latest backlight changes, moving the
locking into _intel_edp_backlight_on/off() and adding it to
intel_edp_backlight_power().

With the above things rebased the patch looks ok to me:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> @@ -2182,9 +2238,11 @@ static void vlv_pre_enable_dp(struct intel_encoder *encoder)
>
> if (is_edp(intel_dp)) {
> /* init power sequencer on this pipe and port */
> + mutex_lock(&dev_priv->pps_mutex);
> intel_dp_init_panel_power_sequencer(dev, intel_dp, &power_seq);
> intel_dp_init_panel_power_sequencer_registers(dev, intel_dp,
> &power_seq);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> intel_enable_dp(encoder);
> @@ -2284,9 +2342,11 @@ static void chv_pre_enable_dp(struct intel_encoder *encoder)
>
> if (is_edp(intel_dp)) {
> /* init power sequencer on this pipe and port */
> + mutex_lock(&dev_priv->pps_mutex);
> intel_dp_init_panel_power_sequencer(dev, intel_dp, &power_seq);
> intel_dp_init_panel_power_sequencer_registers(dev, intel_dp,
> &power_seq);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> intel_enable_dp(encoder);
> @@ -4027,15 +4087,16 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
> struct intel_digital_port *intel_dig_port = enc_to_dig_port(encoder);
> struct intel_dp *intel_dp = &intel_dig_port->dp;
> struct drm_device *dev = intel_dp_to_dev(intel_dp);
> + struct drm_i915_private *dev_priv = dev->dev_private;
>
> drm_dp_aux_unregister(&intel_dp->aux);
> intel_dp_mst_encoder_cleanup(intel_dig_port);
> drm_encoder_cleanup(encoder);
> if (is_edp(intel_dp)) {
> cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> - drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> + mutex_lock(&dev_priv->pps_mutex);
> edp_panel_vdd_off_sync(intel_dp);
> - drm_modeset_unlock(&dev->mode_config.connection_mutex);
> + mutex_unlock(&dev_priv->pps_mutex);
> if (intel_dp->edp_notifier.notifier_call) {
> unregister_reboot_notifier(&intel_dp->edp_notifier);
> intel_dp->edp_notifier.notifier_call = NULL;
> @@ -4047,11 +4108,15 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
> static void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
> {
> struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> + struct drm_device *dev = intel_dp_to_dev(intel_dp);
> + struct drm_i915_private *dev_priv = dev->dev_private;
>
> if (!is_edp(intel_dp))
> return;
>
> + mutex_lock(&dev_priv->pps_mutex);
> edp_panel_vdd_off_sync(intel_dp);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> static void intel_dp_encoder_reset(struct drm_encoder *encoder)
> @@ -4232,6 +4297,8 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
> u32 pp_on, pp_off, pp_div, pp;
> int pp_ctrl_reg, pp_on_reg, pp_off_reg, pp_div_reg;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> if (HAS_PCH_SPLIT(dev)) {
> pp_ctrl_reg = PCH_PP_CONTROL;
> pp_on_reg = PCH_PP_ON_DELAYS;
> @@ -4333,6 +4400,8 @@ intel_dp_init_panel_power_sequencer_registers(struct drm_device *dev,
> int pp_on_reg, pp_off_reg, pp_div_reg;
> enum port port = dp_to_dig_port(intel_dp)->port;
>
> + lockdep_assert_held(&dev_priv->pps_mutex);
> +
> if (HAS_PCH_SPLIT(dev)) {
> pp_on_reg = PCH_PP_ON_DELAYS;
> pp_off_reg = PCH_PP_OFF_DELAYS;
> @@ -4525,9 +4594,11 @@ void intel_edp_panel_vdd_sanitize(struct intel_encoder *intel_encoder)
> if (intel_encoder->type != INTEL_OUTPUT_EDP)
> return;
>
> + mutex_lock(&dev_priv->pps_mutex);
> +
> intel_dp = enc_to_intel_dp(&intel_encoder->base);
> if (!edp_have_panel_vdd(intel_dp))
> - return;
> + goto out;
> /*
> * The VDD bit needs a power domain reference, so if the bit is
> * already enabled when we boot or resume, grab this reference and
> @@ -4539,6 +4610,8 @@ void intel_edp_panel_vdd_sanitize(struct intel_encoder *intel_encoder)
> intel_display_power_get(dev_priv, power_domain);
>
> edp_panel_vdd_schedule_off(intel_dp);
> + out:
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> @@ -4580,7 +4653,9 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> }
>
> /* We now know it's not a ghost, init power sequence regs. */
> + mutex_lock(&dev_priv->pps_mutex);
> intel_dp_init_panel_power_sequencer_registers(dev, intel_dp, power_seq);
> + mutex_unlock(&dev_priv->pps_mutex);
>
> mutex_lock(&dev->mode_config.mutex);
> edid = drm_get_edid(connector, &intel_dp->aux.ddc);
> @@ -4712,8 +4787,10 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
> }
>
> if (is_edp(intel_dp)) {
> + mutex_lock(&dev_priv->pps_mutex);
> intel_dp_init_panel_power_timestamps(intel_dp);
> intel_dp_init_panel_power_sequencer(dev, intel_dp, &power_seq);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
>
> intel_dp_aux_init(intel_dp, intel_connector);
> @@ -4729,9 +4806,9 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
> drm_dp_aux_unregister(&intel_dp->aux);
> if (is_edp(intel_dp)) {
> cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> - drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> + mutex_lock(&dev_priv->pps_mutex);
> edp_panel_vdd_off_sync(intel_dp);
> - drm_modeset_unlock(&dev->mode_config.connection_mutex);
> + mutex_unlock(&dev_priv->pps_mutex);
> }
> drm_connector_unregister(connector);
> drm_connector_cleanup(connector);

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