Re: [PATCH v2 5/7] drm/i915: check LSPCON vendor OUI

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Hey,

Op 09-08-17 om 08:46 schreef Shashank Sharma:
> Intel LSPCON chip is provided by 2 vendors:
> - Megachips America (MCA)
> - Parade technologies (Parade tech)
>
> Its important to know the vendor of this chip, as the address to
> write AVI infoframes is different for those two.
>
> This patch reads the vendor OUI signature, and marks into LSPCON
> encoder structure for future usages.
>
> This patch also does a small re-arrangement of the code, by moving
> lspcon mode change into probe function.
>
> V2: Use dp->desc for OUI detection, dont add a helper for this
>     (Ville)
>
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_drv.h    |  6 ++++
>  drivers/gpu/drm/i915/intel_lspcon.c | 69 +++++++++++++++++++++++++++++--------
>  2 files changed, 61 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 7eadac0..adab635 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1043,9 +1043,15 @@ struct intel_dp {
>  	struct intel_dp_compliance compliance;
>  };
>  
> +enum lspcon_vendor {
> +	LSPCON_VENDOR_MCA,
> +	LSPCON_VENDOR_PARADE
> +};
> +
>  struct intel_lspcon {
>  	bool active;
>  	enum drm_lspcon_mode mode;
> +	enum lspcon_vendor vendor;
>  };
>  
>  struct intel_digital_port {
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index 5abef482..93507c5 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -27,6 +27,10 @@
>  #include <drm/drm_dp_dual_mode_helper.h>
>  #include "intel_drv.h"
>  
> +/* LSPCON OUI Vendor ID(signatures) */
> +#define LSPCON_VENDOR_PARADE_OUI 0x001CF8
> +#define LSPCON_VENDOR_MCA_OUI 0x0060AD
> +
>  static struct intel_dp *lspcon_to_intel_dp(struct intel_lspcon *lspcon)
>  {
>  	struct intel_digital_port *dig_port =
> @@ -50,6 +54,40 @@ static const char *lspcon_mode_name(enum drm_lspcon_mode mode)
>  	}
>  }
>  
> +static bool lspcon_detect_vendor(struct intel_lspcon *lspcon)
> +{
> +	struct intel_dp *dp = lspcon_to_intel_dp(lspcon);
> +	struct drm_dp_dpcd_ident *ident;
> +	u32 vendor_oui;
> +
> +	if (drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd))) {
> +		DRM_ERROR("Can't read description\n");
> +		return false;
> +	}
> +
> +	ident = &dp->desc.ident;
> +	vendor_oui = (ident->oui[0] << 16) | (ident->oui[1] << 8) |
> +		      ident->oui[2];
> +
> +	switch (vendor_oui) {
> +	case LSPCON_VENDOR_MCA_OUI:
> +		lspcon->vendor = LSPCON_VENDOR_MCA;
> +		DRM_DEBUG_KMS("Vendor: Mega Chips\n");
> +		break;
> +
> +	case LSPCON_VENDOR_PARADE_OUI:
> +		lspcon->vendor = LSPCON_VENDOR_PARADE;
> +		DRM_DEBUG_KMS("Vendor: Parade Tech\n");
> +		break;
> +
> +	default:
> +		DRM_ERROR("Invalid/Unknown vendor OUI\n");
MISSING_CASE(vendor_oui) ?
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
>  static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
>  {
>  	enum drm_lspcon_mode current_mode;
> @@ -151,7 +189,18 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
>  	/* Yay ... got a LSPCON device */
>  	DRM_DEBUG_KMS("LSPCON detected\n");
>  	lspcon->mode = lspcon_wait_mode(lspcon, expected_mode);
> -	lspcon->active = true;
> +
> +	/*
> +	 * In the SW state machine, lets Put LSPCON in PCON mode only.
> +	 * In this way, it will work with both HDMI 1.4 sinks as well as HDMI
> +	 * 2.0 sinks.
> +	 */
> +	if (lspcon->active && lspcon->mode != DRM_LSPCON_MODE_PCON) {
> +		if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON) < 0) {
> +			DRM_ERROR("LSPCON mode change to PCON failed\n");
> +			return false;
> +		}
> +	}
>  	return true;
>  }
>  
> @@ -223,25 +272,17 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>  		return false;
>  	}
>  
> -	/*
> -	* In the SW state machine, lets Put LSPCON in PCON mode only.
> -	* In this way, it will work with both HDMI 1.4 sinks as well as HDMI
> -	* 2.0 sinks.
> -	*/
> -	if (lspcon->active && lspcon->mode != DRM_LSPCON_MODE_PCON) {
> -		if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON) < 0) {
> -			DRM_ERROR("LSPCON mode change to PCON failed\n");
> -			return false;
> -		}
> -	}
> -
>  	if (!intel_dp_read_dpcd(dp)) {
>  		DRM_ERROR("LSPCON DPCD read failed\n");
>  		return false;
>  	}
>  
> -	drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd));
> +	if (!lspcon_detect_vendor(lspcon)) {
> +		DRM_ERROR("LSPCON vendor detection failed\n");
> +		return false;
> +	}
Error seems double here, lspcon_detect_vendor should already succeed.

Same for lspcon_probe I think, better to upgrade the DRM_DEBUG_KMS failure there to DRM_ERROR there and remove the one from lspcon_init.
>  
> +	lspcon->active = true;
>  	DRM_DEBUG_KMS("Success: LSPCON init\n");
>  	return true;
>  }


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