Re: [PATCH v2 5/8] drm/i915/lspcon: Fail LSPCON probe if the start of DPCD can't be read

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 24 Oct 2016, Imre Deak <imre.deak@intel.com> wrote:
> All types of DP devices (eDP, DP sink, DP branch) will fail their probe
> if the start of DPCD can't be read. The LSPCON PCON functionality also
> depends on accessing this area, so fail the probe if the read fails.
>
> Cc: Shashank Sharma <shashank.sharma@intel.com>
> Signed-off-by: Imre Deak <imre.deak@intel.com>

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


> ---
>  drivers/gpu/drm/i915/intel_dp.c     | 2 +-
>  drivers/gpu/drm/i915/intel_drv.h    | 2 ++
>  drivers/gpu/drm/i915/intel_lspcon.c | 5 +++++
>  3 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 726fdf2..62c5512 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3495,7 +3495,7 @@ intel_dp_link_down(struct intel_dp *intel_dp)
>  	intel_dp->DP = DP;
>  }
>  
> -static bool
> +bool
>  intel_dp_read_dpcd(struct intel_dp *intel_dp)
>  {
>  	if (drm_dp_dpcd_read(&intel_dp->aux, 0x000, intel_dp->dpcd,
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 4c9f953..ff9d2dc 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1461,6 +1461,8 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
>  	return ~((1 << lane_count) - 1) & 0xf;
>  }
>  
> +bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
> +
>  /* intel_dp_aux_backlight.c */
>  int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
>  
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index 632149c..23b817a 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -131,6 +131,11 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>  		}
>  	}
>  
> +	if (!intel_dp_read_dpcd(dp)) {
> +		DRM_ERROR("LSPCON DPCD read failed\n");
> +		return false;
> +	}
> +
>  	DRM_DEBUG_KMS("Success: LSPCON init\n");
>  	return true;
>  }

-- 
Jani Nikula, Intel Open Source Technology Center
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