[Intel-gfx] [PATCH 2/2] drm/i915: Find unclaimed MMIO writes.

[Paulo Zanoni]

2012/8/20 Ben Widawsky <ben at bwidawsk.net>:
> ERR_INT on HSW will display unclaimed MMIO accesses. This can be either
> the result of a driver bug writing to an invalid addresses, or the
> result of RC6.
>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>

For both patches:
Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Tested-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

This is a pretty awesome change! It will really help the new hardware
enablement/debugging efforts.

We should volunteer someone to look at the other ERR_INT bits.

> ---
>  drivers/gpu/drm/i915/i915_drv.c | 4 ++++
>  drivers/gpu/drm/i915/i915_reg.h | 1 +
>  2 files changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 845e390..255087f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1182,6 +1182,10 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
>         if (unlikely(__fifo_ret)) { \
>                 gen6_gt_check_fifodbg(dev_priv); \
>         } \
> +       if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
> +               DRM_ERROR("Unclaimed write to %x\n", reg); \
> +               writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT);  \
> +       } \
>  }
>  __i915_write(8, b)
>  __i915_write(16, w)
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index d4a7d73..bab4762 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -508,6 +508,7 @@
>
>  #define ERROR_GEN6     0x040a0
>  #define GEN7_ERR_INT   0x44040
> +#define   ERR_INT_MMIO_UNCLAIMED (1<<13)
>
>  /* GM45+ chicken bits -- debug workaround bits that may be required
>   * for various sorts of correct behavior.  The top 16 bits of each are
> --
> 1.7.11.5
>
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-- 
Paulo Zanoni