Turn a fatal lockup into a merely blank display with lots of shouty
messages.
v2: Whilst in the area, convert the other BUG_ON into less fatal errors.
In particular, note that we may be called on a PCH platform not using
PLLs, such as Haswell, and so we do not always want to BUG_ON(!pll)
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_display.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 12dba60..f9e1e1c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1473,14 +1473,18 @@ out_unlock:
static void intel_enable_pch_pll(struct intel_crtc *intel_crtc)
{
struct drm_i915_private *dev_priv = intel_crtc->base.dev->dev_private;
- struct intel_pch_pll *pll = intel_crtc->pch_pll;
+ struct intel_pch_pll *pll;
int reg;
u32 val;
- /* PCH only available on ILK+ */
+ /* PCH PLLs only available on ILK, SNB and IVB */
BUG_ON(dev_priv->info->gen < 5);
- BUG_ON(pll == NULL);
- BUG_ON(pll->refcount == 0);
+ pll = intel_crtc->pch_pll;
+ if (pll == NULL)
+ return;
+
+ if (WARN_ON(pll->refcount == 0))
+ return;
DRM_DEBUG_KMS("enable PCH PLL %x (active %d, on? %d)for crtc %d\n",
pll->pll_reg, pll->active, pll->on,
@@ -1518,13 +1522,18 @@ static void intel_disable_pch_pll(struct intel_crtc *intel_crtc)
if (pll == NULL)
return;
- BUG_ON(pll->refcount == 0);
+ if (WARN_ON(pll->refcount == 0))
+ return;
DRM_DEBUG_KMS("disable PCH PLL %x (active %d, on? %d) for crtc %d\n",
pll->pll_reg, pll->active, pll->on,
intel_crtc->base.base.id);
- BUG_ON(pll->active == 0);
+ if (WARN_ON(pll->active == 0)) {
+ assert_pch_pll_disabled(dev_priv, intel_crtc);
+ return;
+ }
+
if (--pll->active) {
assert_pch_pll_enabled(dev_priv, intel_crtc);
return;
--
1.7.10
