From: Paulo Zanoni <paulo.r.zan...@intel.com> The eDP spec defines some points where after you do action A, you have to wait some time before action B. The thing is that in our driver action B does not happen exactly after action A, but we still use msleep() calls directly. What this patch does is that we record the timestamp of when action A happened, then, just before action B, we look at how much time has passed and only sleep the remaining amount needed.
With this change, I am able to save about 5-20ms (out of the total 200ms) of the backlight_off delay and completely skip the 1ms backlight_on delay. The 600ms vdd_off delay doesn't happen during normal usage anymore due to a previous patch. v2: - Rename ironlake_wait_jiffies_delay to intel_wait_until_after and move it to intel_display.c - Fix the msleep call: diff is in jiffies v3: - Use "tmp_jiffies" so we don't need to worry about the value of "jiffies" advancing while we're doing the math. Signed-off-by: Paulo Zanoni <paulo.r.zan...@intel.com> --- drivers/gpu/drm/i915/intel_display.c | 18 ++++++++++++++++++ drivers/gpu/drm/i915/intel_dp.c | 26 +++++++++++++++++++++++--- drivers/gpu/drm/i915/intel_drv.h | 4 ++++ 3 files changed, 45 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3c59b67..0c238dd 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -806,6 +806,24 @@ void intel_wait_for_vblank(struct drm_device *dev, int pipe) DRM_DEBUG_KMS("vblank wait timed out\n"); } +/* If you need to wait X ms between events A and B, but event B doesn't happen + * exactly after event A, you record the timestamp (jiffies) of when event A + * happened, then just before event B you call intel_wait_until_after and pass + * the timestamp as the first argument, and X as the second argument. */ +void intel_wait_until_after(unsigned long timestamp, int to_wait_ms) +{ + unsigned long target = timestamp + msecs_to_jiffies(to_wait_ms); + unsigned long diff; + /* Don't re-read the value of "jiffies" every time since it may change + * behind our back and break the math. */ + unsigned long tmp_jiffies = jiffies; + + if (time_after(target, tmp_jiffies)) { + diff = (long)target - (long)tmp_jiffies; + msleep(jiffies_to_msecs(diff)); + } +} + static bool pipe_dsl_stopped(struct drm_device *dev, enum pipe pipe) { struct drm_i915_private *dev_priv = dev->dev_private; diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index a2aace2..79f7ec2 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1056,9 +1056,26 @@ static void ironlake_wait_panel_off(struct intel_dp *intel_dp) static void ironlake_wait_panel_power_cycle(struct intel_dp *intel_dp) { DRM_DEBUG_KMS("Wait for panel power cycle\n"); + + /* When we disable the VDD override bit last we have to do the manual + * wait. */ + intel_wait_until_after(intel_dp->last_power_cycle, + intel_dp->panel_power_cycle_delay); + ironlake_wait_panel_status(intel_dp, IDLE_CYCLE_MASK, IDLE_CYCLE_VALUE); } +static void ironlake_wait_backlight_on(struct intel_dp *intel_dp) +{ + intel_wait_until_after(intel_dp->last_power_on, + intel_dp->backlight_on_delay); +} + +static void ironlake_edp_wait_backlight_off(struct intel_dp *intel_dp) +{ + intel_wait_until_after(intel_dp->last_backlight_off, + intel_dp->backlight_off_delay); +} /* Read the current pp_control value, unlocking the register if it * is locked @@ -1144,7 +1161,7 @@ static void ironlake_panel_vdd_off_sync(struct intel_dp *intel_dp) I915_READ(pp_stat_reg), I915_READ(pp_ctrl_reg)); if ((pp & POWER_TARGET_ON) == 0) - msleep(intel_dp->panel_power_cycle_delay); + intel_dp->last_power_cycle = jiffies; } } @@ -1217,6 +1234,7 @@ void ironlake_edp_panel_on(struct intel_dp *intel_dp) POSTING_READ(pp_ctrl_reg); ironlake_wait_panel_on(intel_dp); + intel_dp->last_power_on = jiffies; if (IS_GEN5(dev)) { pp |= PANEL_POWER_RESET; /* restore panel reset bit */ @@ -1237,6 +1255,8 @@ void ironlake_edp_panel_off(struct intel_dp *intel_dp) DRM_DEBUG_KMS("Turn eDP power off\n"); + ironlake_edp_wait_backlight_off(intel_dp); + pp = ironlake_get_pp_control(intel_dp); /* We need to switch off panel power _and_ force vdd, for otherwise some * panels get very unhappy and cease to work. */ @@ -1268,7 +1288,7 @@ void ironlake_edp_backlight_on(struct intel_dp *intel_dp) * link. So delay a bit to make sure the image is solid before * allowing it to appear. */ - msleep(intel_dp->backlight_on_delay); + ironlake_wait_backlight_on(intel_dp); pp = ironlake_get_pp_control(intel_dp); pp |= EDP_BLC_ENABLE; @@ -1300,7 +1320,7 @@ void ironlake_edp_backlight_off(struct intel_dp *intel_dp) I915_WRITE(pp_ctrl_reg, pp); POSTING_READ(pp_ctrl_reg); - msleep(intel_dp->backlight_off_delay); + intel_dp->last_backlight_off = jiffies; } static void ironlake_edp_pll_on(struct intel_dp *intel_dp) diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index ea62673..eda8ee8 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -484,6 +484,9 @@ struct intel_dp { int backlight_off_delay; struct delayed_work panel_vdd_work; bool want_panel_vdd; + unsigned long last_power_cycle; + unsigned long last_power_on; + unsigned long last_backlight_off; bool psr_setup_done; struct intel_connector *attached_connector; }; @@ -707,6 +710,7 @@ void hsw_enable_ips(struct intel_crtc *crtc); void hsw_disable_ips(struct intel_crtc *crtc); void intel_display_set_init_power(struct drm_device *dev, bool enable); int valleyview_get_vco(struct drm_i915_private *dev_priv); +void intel_wait_until_after(unsigned long timestamp, int to_wait_ms); /* intel_dp.c */ void intel_dp_init(struct drm_device *dev, int output_reg, enum port port); -- 1.8.3.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx