[Intel-gfx] [PATCH v2] drm/i915: Warn if a pipe is enabled with a bogus port

[Paulo Zanoni]

Hi

2013/3/25 Damien Lespiau <damien.lespiau at intel.com>:
> If TRANS_DDI_FUNC_CTL has been wrongly programmed with an incorrect
> port, we are currently trying to read PORT_CLK_SEL(port) with an
> uninitialized value.
>
> Handle that case by returning PORT_CLK_SEL_NONE and warning about it.
>
> v2: Move the warning inside intel_ddi_get_crtc_pll (Paulo Zanoni)
>
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index d26147c..258e38e 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1160,7 +1160,7 @@ static uint32_t intel_ddi_get_crtc_pll(struct drm_i915_private *dev_priv,
>                                        enum pipe pipe)
>  {
>         uint32_t temp, ret;
> -       enum port port;
> +       enum port port = I915_MAX_PORTS;
>         enum transcoder cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv,
>                                                                       pipe);
>         int i;
> @@ -1176,10 +1176,16 @@ static uint32_t intel_ddi_get_crtc_pll(struct drm_i915_private *dev_priv,
>                                 port = i;
>         }
>
> -       ret = I915_READ(PORT_CLK_SEL(port));
> -
> -       DRM_DEBUG_KMS("Pipe %c connected to port %c using clock 0x%08x\n",
> -                     pipe_name(pipe), port_name(port), ret);
> +       if (port == I915_MAX_PORTS) {
> +               WARN(1, "Pipe %c enabled on an unknown port\n",
> +                    pipe_name(pipe));
> +               ret = PORT_CLK_SEL_NONE;
> +       } else {
> +               ret = I915_READ(PORT_CLK_SEL(port));
> +               DRM_DEBUG_KMS("Pipe %c connected to port %c using clock "
> +                             "0x%08x\n", pipe_name(pipe), port_name(port),
> +                             ret);
> +       }
>
>         return ret;
>  }
> --
> 1.7.11.7
>
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-- 
Paulo Zanoni