[Intel-gfx] [PATCH 21/49] drm/i915/bxt: WARN in case BXT unused gmbus ports are accessed

Jani Nikula jani.nikula at linux.intel.com
Wed Mar 25 09:49:12 PDT 2015


On Tue, 17 Mar 2015, Imre Deak <imre.deak at intel.com> wrote:
> From: "A.Sunil Kamath" <sunil.kamath at intel.com>
>
> This patch will WARN if unused gmbus ports gets accessed for
> BXT using gmbus_get_adapter also ensure that only valid ports
> of BXT gets used. For BXT its more important to do this as it
> has only 3 valid ports and structure has empty content otherwise.
>
> Because of additonal IS_BROXTON check an additional "dev"
> argument is added to intel_gmbus_is_port_valid. Also added
> related changes in other places from where this function is accessed.
>
> v1: This WARN patch is added as per review comments from
> Daniel Vetter on gmbus BXT patch
>
> v2: Changed get_adapter to have only one is_port_valid call
> according to review comments from M Satheeshakrishna.
>
> v3: Early bail out on errors according to review comments from
> Daniel Vetter.
>
> Issue: VIZ-3574
> Signed-off-by: A.Sunil Kamath <sunil.kamath at intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h   | 8 ++++++--
>  drivers/gpu/drm/i915/intel_bios.c | 3 ++-
>  drivers/gpu/drm/i915/intel_dvo.c  | 2 +-
>  drivers/gpu/drm/i915/intel_i2c.c  | 9 ++++++---
>  drivers/gpu/drm/i915/intel_lvds.c | 2 +-
>  drivers/gpu/drm/i915/intel_sdvo.c | 4 +++-
>  6 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8fb7cc0..52e5f18 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3037,9 +3037,13 @@ void i915_teardown_sysfs(struct drm_device *dev_priv);
>  /* intel_i2c.c */
>  extern int intel_setup_gmbus(struct drm_device *dev);
>  extern void intel_teardown_gmbus(struct drm_device *dev);
> -static inline bool intel_gmbus_is_port_valid(unsigned port)
> +static inline bool
> +intel_gmbus_is_port_valid(struct drm_device *dev, unsigned port)

It's probably better to pass dev_priv here, and fix all the call
sites. Removes a bunch of extra local vars down there.

With this fixed,

Reviewed-by: Jani Nikula <jani.nikula at intel.com>


>  {
> -	return (port >= GMBUS_PORT_SSC && port <= GMBUS_PORT_DPD);
> +	if (IS_BROXTON(dev))
> +		return port >= GMBUS_PORT_DPC && port <= GMBUS_PORT_DPD;

It's seriously confusing that _DPB is within that range... but not a
problem in this patch per se.

> +	else
> +		return port >= GMBUS_PORT_SSC && port <= GMBUS_PORT_DPD;
>  }
>  
>  extern struct i2c_adapter *intel_gmbus_get_adapter(
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index c684085..e423cc8 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -431,6 +431,7 @@ parse_general_definitions(struct drm_i915_private *dev_priv,
>  			  struct bdb_header *bdb)
>  {
>  	struct bdb_general_definitions *general;
> +	struct drm_device *dev = dev_priv->dev;
>  
>  	general = find_section(bdb, BDB_GENERAL_DEFINITIONS);
>  	if (general) {
> @@ -438,7 +439,7 @@ parse_general_definitions(struct drm_i915_private *dev_priv,
>  		if (block_size >= sizeof(*general)) {
>  			int bus_pin = general->crt_ddc_gmbus_pin;
>  			DRM_DEBUG_KMS("crt_ddc_bus_pin: %d\n", bus_pin);
> -			if (intel_gmbus_is_port_valid(bus_pin))
> +			if (intel_gmbus_is_port_valid(dev, bus_pin))
>  				dev_priv->vbt.crt_ddc_pin = bus_pin;
>  		} else {
>  			DRM_DEBUG_KMS("BDB_GD too small (%d). Invalid.\n",
> diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
> index d857951..27d5b9a 100644
> --- a/drivers/gpu/drm/i915/intel_dvo.c
> +++ b/drivers/gpu/drm/i915/intel_dvo.c
> @@ -499,7 +499,7 @@ void intel_dvo_init(struct drm_device *dev)
>  		 * special cases, but otherwise default to what's defined
>  		 * in the spec.
>  		 */
> -		if (intel_gmbus_is_port_valid(dvo->gpio))
> +		if (intel_gmbus_is_port_valid(dev, dvo->gpio))
>  			gpio = dvo->gpio;
>  		else if (dvo->type == INTEL_DVO_CHIP_LVDS)
>  			gpio = GMBUS_PORT_SSC;
> diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
> index 3aa31e1..06892b5 100644
> --- a/drivers/gpu/drm/i915/intel_i2c.c
> +++ b/drivers/gpu/drm/i915/intel_i2c.c
> @@ -619,10 +619,13 @@ err:
>  struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
>  					    unsigned port)
>  {
> -	WARN_ON(!intel_gmbus_is_port_valid(port));
> +	struct drm_device *dev = dev_priv->dev;
> +
> +	if (WARN_ON(!intel_gmbus_is_port_valid(dev, port)))
> +		return NULL;
> +
>  	/* -1 to map pin pair to gmbus index */
> -	return (intel_gmbus_is_port_valid(port)) ?
> -		&dev_priv->gmbus[port - 1].adapter : NULL;
> +	return &dev_priv->gmbus[port - 1].adapter;
>  }
>  
>  void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index 24e8730..094b88e 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -780,7 +780,7 @@ static bool lvds_is_present_in_vbt(struct drm_device *dev,
>  		    child->device_type != DEVICE_TYPE_LFP)
>  			continue;
>  
> -		if (intel_gmbus_is_port_valid(child->i2c_pin))
> +		if (intel_gmbus_is_port_valid(dev, child->i2c_pin))
>  			*i2c_pin = child->i2c_pin;
>  
>  		/* However, we cannot trust the BIOS writers to populate
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> index 9e554c2..d68936e 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -2283,6 +2283,7 @@ intel_sdvo_select_i2c_bus(struct drm_i915_private *dev_priv,
>  			  struct intel_sdvo *sdvo, u32 reg)
>  {
>  	struct sdvo_device_mapping *mapping;
> +	struct drm_device *dev = dev_priv->dev;
>  	u8 pin;
>  
>  	if (sdvo->is_sdvob)
> @@ -2290,7 +2291,8 @@ intel_sdvo_select_i2c_bus(struct drm_i915_private *dev_priv,
>  	else
>  		mapping = &dev_priv->sdvo_mappings[1];
>  
> -	if (mapping->initialized && intel_gmbus_is_port_valid(mapping->i2c_pin))
> +	if (mapping->initialized &&
> +		intel_gmbus_is_port_valid(dev, mapping->i2c_pin))
>  		pin = mapping->i2c_pin;
>  	else
>  		pin = GMBUS_PORT_DPB;
> -- 
> 2.1.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center


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