diff options
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 9b8c1e06a787..3f62be0fb5c5 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2736,6 +2736,12 @@ void vlv_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine); #define I915_READ_NOTRACE(reg) dev_priv->uncore.funcs.mmio_readl(dev_priv, (reg), false) #define I915_WRITE_NOTRACE(reg, val) dev_priv->uncore.funcs.mmio_writel(dev_priv, (reg), (val), false) +/* Be very careful with read/write 64-bit values. On 32-bit machines, they + * will be implemented using 2 32-bit writes in an arbitrary order with + * an arbitrary delay between them. This can cause the hardware to + * act upon the intermediate value, possibly leading to corruption and + * machine death. You have been warned. + */ #define I915_WRITE64(reg, val) dev_priv->uncore.funcs.mmio_writeq(dev_priv, (reg), (val), true) #define I915_READ64(reg) dev_priv->uncore.funcs.mmio_readq(dev_priv, (reg), true) |