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

[Timo Aaltonen]

On 13.08.2015 16:14, David Weinehall wrote:
> On Wed, Aug 12, 2015 at 05:19:35PM +0300, Jani Nikula wrote:
>> 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
>>> +	 */
>>>  	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);
>>
>> drivers/gpu/drm/i915/intel_bios.c: In function ‘parse_device_mapping’:
>> drivers/gpu/drm/i915/intel_bios.c:1058:3: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
>>    DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
>>    ^
>>   CC [M]  drivers/gpu/drm/i915/intel_fifo_underrun.o
> 
> Well spotted.  Or rather, stupid of me to forget that sizeof yields
> size_t as type, thus necessitating %zu as conversion specifier.
> 
> Fixed version:
> 
> Expand common_child_dev_config to be able to fit all information
> defined by the latest VBT specification.
> 
> v2: Use proper conversion specifier for size_t (%zu)
> 
> 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..5673ed53797b 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
> +	 */
>  	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 %zu); 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

Please apply this, fixes issues on some machine(s) here. Probably also
cc:stable since it applies to BSW as well as SKL.

and the upstream bug could be referenced too, it's
https://bugs.freedesktop.org/show_bug.cgi?id=91613

-- 
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