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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2010-08-07 11:01:35 +0100 |
|---|---|---|
| committer | Eric Anholt <eric@anholt.net> | 2010-08-09 11:24:35 -0700 |
| commit | 913d8d110078788c14812dce8bb62c37946821d2 (patch) | |
| tree | 982a622078194b438bf75d0ee4c77cf1e4f0260e /drivers/gpu/drm/i915/intel_lvds.c | |
| parent | dd785e35cb3c430c2290d351e67715864f7e5db5 (diff) | |
| download | linux-913d8d110078788c14812dce8bb62c37946821d2.tar.gz linux-913d8d110078788c14812dce8bb62c37946821d2.tar.bz2 linux-913d8d110078788c14812dce8bb62c37946821d2.zip | |
drm/i915: Ensure that while(INREG()) are bounded (v2)
Add a new macro, wait_for, to simplify the act of waiting on a register
to change state. wait_for() takes three arguments, the condition to
inspect on every loop, the maximum amount of time to wait and whether to
yield the cpu for a length of time after each check.
v2: Upgrade failure messages to DRM_ERROR on the suggestion of
Eric Anholt. We do not expect to hit these conditions as they reflect
programming errors, so if we do we want to be notified.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_lvds.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_lvds.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index cb5821eb59b6..b819c1081147 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -96,7 +96,7 @@ static u32 intel_lvds_get_max_backlight(struct drm_device *dev) static void intel_lvds_set_power(struct drm_device *dev, bool on) { struct drm_i915_private *dev_priv = dev->dev_private; - u32 pp_status, ctl_reg, status_reg, lvds_reg; + u32 ctl_reg, status_reg, lvds_reg; if (HAS_PCH_SPLIT(dev)) { ctl_reg = PCH_PP_CONTROL; @@ -114,9 +114,8 @@ static void intel_lvds_set_power(struct drm_device *dev, bool on) I915_WRITE(ctl_reg, I915_READ(ctl_reg) | POWER_TARGET_ON); - do { - pp_status = I915_READ(status_reg); - } while ((pp_status & PP_ON) == 0); + if (wait_for(I915_READ(status_reg) & PP_ON, 1000, 0)) + DRM_ERROR("timed out waiting to enable LVDS pipe"); intel_lvds_set_backlight(dev, dev_priv->backlight_duty_cycle); } else { @@ -124,9 +123,8 @@ static void intel_lvds_set_power(struct drm_device *dev, bool on) I915_WRITE(ctl_reg, I915_READ(ctl_reg) & ~POWER_TARGET_ON); - do { - pp_status = I915_READ(status_reg); - } while (pp_status & PP_ON); + if (wait_for((I915_READ(status_reg) & PP_ON) == 0, 1000, 0)) + DRM_ERROR("timed out waiting for LVDS pipe to turn off"); I915_WRITE(lvds_reg, I915_READ(lvds_reg) & ~LVDS_PORT_EN); POSTING_READ(lvds_reg); |