This is similar to a patch I wrote several months ago. It's been updated
for the new FORCEWAKE_MT. As recommended by Chris Wilson, use WARN()
instead of DRM_ERROR, so we can get a backtrace.
This shouldn't impact performance too much as the extra register read
can replace the POSTING_READ we had previously.
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
drivers/gpu/drm/i915/i915_drv.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 1658cfd..a8b6a78 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -379,16 +379,27 @@ void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
dev_priv->display.force_wake_get(dev_priv);
}
+static void gen6_gt_check_fifodbg(struct drm_i915_private *dev_priv)
+{
+ u32 gtfifodbg;
+ gtfifodbg = I915_READ_NOTRACE(GTFIFODBG);
+ if (WARN(gtfifodbg & GT_FIFO_CPU_ERROR_MASK,
+ "MMIO read or write has been dropped %x\n", gtfifodbg))
+ I915_WRITE_NOTRACE(GTFIFODBG, GT_FIFO_CPU_ERROR_MASK);
+}
+
void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
{
I915_WRITE_NOTRACE(FORCEWAKE, 0);
- POSTING_READ(FORCEWAKE);
+ /* The below doubles as a POSTING_READ */
+ gen6_gt_check_fifodbg(dev_priv);
}
void __gen6_gt_force_wake_mt_put(struct drm_i915_private *dev_priv)
{
I915_WRITE_NOTRACE(FORCEWAKE_MT, (1<<16) | 0);
- POSTING_READ(FORCEWAKE_MT);
+ /* The below doubles as a POSTING_READ */
+ gen6_gt_check_fifodbg(dev_priv);
}
/*
--
1.7.9
