[Intel-gfx] [PATCH 1/2 v2 addendum] drm/i915: Allow parsing of variable size child device entries from VBT

[Jani Nikula]

On Wed, 12 Aug 2015, David Weinehall <david.weinehall at linux.intel.com> wrote:
> Some more fixup is needed; the bits from Antti's patch
> that actually expanded the struct to fully fit the newer
> versions of the child_device_config was part of the second
> patch; since that patch hasn't been merged yet we need this bit:
>
> This applies on top of the patch you already merged
> (the Iboost patch will need corresponding adjustment to
>  remove the changes I split out):
>
> Expand common_child_dev_config to be able to fit all information
> defined by the latest VBT specification.
>
> Signed-off-by: David Weinehall <david.weinehall at linux.intel.com>
> CC: Antti Koskipaa <antti.koskipaa at linux.intel.com>
> ---
>  intel_bios.c |    7 ++++++-
>  intel_bios.h |    4 ++++
>  2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 990acc20771a..40e2cc4e7419 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -1038,6 +1038,10 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
>  		return;
>  	}
> +	/* Remember to keep this in sync with child_device_config;
> +	 * whenever a new feature is added to BDB that causes that
> +	 * struct to grow this needs to be updated too
> +	 */

BUILD_BUG_ON(something about sizeof child device config) ?

>  	if (bdb->version < 195) {
>  		expected_size = 33;
>  	} else if (bdb->version == 195) {
> @@ -1051,7 +1055,8 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  	}
>  
>  	if (expected_size > sizeof(*p_child)) {
> -		DRM_ERROR("child_device_config cannot fit in p_child\n");
> +		DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
> +			  expected_size, sizeof(*p_child), bdb->version);
>  		return;
>  	}
>  
> diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
> index f7ad6a585129..71cb96f77870 100644
> --- a/drivers/gpu/drm/i915/intel_bios.h
> +++ b/drivers/gpu/drm/i915/intel_bios.h
> @@ -239,6 +239,10 @@ struct common_child_dev_config {
>  	u8 not_common2[2];
>  	u8 ddc_pin;
>  	u16 edid_ptr;
> +	u8 obsolete;
> +	u8 flags_1;
> +	u8 not_common3[13];
> +	u8 iboost_level;
>  } __packed;
>  
>  /* This field changes depending on the BDB version, so the most reliable way to
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-- 
Jani Nikula, Intel Open Source Technology Center