If the pipe or plane is already enabled, then we do not need to enable it again and can skip the delay. Similarly if it is already disabled when we want to disable it, we can also skip it.
This fixes a regression from b24e717988, which caused the LVDS output on one PineView machine to become corrupt after changing orientation several times. References: https://bugs.freedesktop.org/show_bug.cgi?id=34601 Cc: Jesse Barnes <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Reviewed-by: Keith Packard <[email protected]> --- drivers/gpu/drm/i915/intel_display.c | 24 ++++++++++++++++-------- 1 files changed, 16 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3bc6ab5..841f039 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -1516,8 +1516,10 @@ static void intel_enable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe, reg = PIPECONF(pipe); val = I915_READ(reg); - val |= PIPECONF_ENABLE; - I915_WRITE(reg, val); + if (val & PIPECONF_ENABLE) + return; + + I915_WRITE(reg, val | PIPECONF_ENABLE); intel_wait_for_vblank(dev_priv->dev, pipe); } @@ -1551,8 +1553,10 @@ static void intel_disable_pipe(struct drm_i915_private *dev_priv, reg = PIPECONF(pipe); val = I915_READ(reg); - val &= ~PIPECONF_ENABLE; - I915_WRITE(reg, val); + if ((val & PIPECONF_ENABLE) == 0) + return; + + I915_WRITE(reg, val & ~PIPECONF_ENABLE); intel_wait_for_pipe_off(dev_priv->dev, pipe); } @@ -1575,8 +1579,10 @@ static void intel_enable_plane(struct drm_i915_private *dev_priv, reg = DSPCNTR(plane); val = I915_READ(reg); - val |= DISPLAY_PLANE_ENABLE; - I915_WRITE(reg, val); + if (val & DISPLAY_PLANE_ENABLE) + return; + + I915_WRITE(reg, val | DISPLAY_PLANE_ENABLE); intel_wait_for_vblank(dev_priv->dev, pipe); } @@ -1607,8 +1613,10 @@ static void intel_disable_plane(struct drm_i915_private *dev_priv, reg = DSPCNTR(plane); val = I915_READ(reg); - val &= ~DISPLAY_PLANE_ENABLE; - I915_WRITE(reg, val); + if ((val & DISPLAY_PLANE_ENABLE) == 0) + return; + + I915_WRITE(reg, val & ~DISPLAY_PLANE_ENABLE); intel_flush_display_plane(dev_priv, plane); intel_wait_for_vblank(dev_priv->dev, pipe); } -- 1.7.4.1 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
