Re: [PATCH 3/4] drm/i915/dp: Fetch downstream port info if needed during DPCD fetch

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

On Mon, 17 Sep 2012, Adam Jackson <ajax@redhat.com> wrote:
> Signed-off-by: Adam Jackson <ajax@redhat.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   25 ++++++++++++++++++++-----
>  1 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ace757a..92939bd 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -39,6 +39,7 @@
>  #include "drm_dp_helper.h"
>  
>  #define DP_RECEIVER_CAP_SIZE	0xf
> +#define DP_MAX_DOWNSTREAM_PORTS 0xf
>  #define DP_LINK_STATUS_SIZE	6
>  #define DP_LINK_CHECK_TIMEOUT	(10 * 1000)
>  
> @@ -56,6 +57,7 @@ struct intel_dp {
>  	uint8_t link_bw;
>  	uint8_t lane_count;
>  	uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
> +	uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
>  	struct i2c_adapter adapter;
>  	struct i2c_algo_dp_aux_data algo;
>  	bool is_pch_edp;
> @@ -1968,12 +1970,25 @@ static bool
>  intel_dp_get_dpcd(struct intel_dp *intel_dp)
>  {
>  	if (intel_dp_aux_native_read_retry(intel_dp, 0x000, intel_dp->dpcd,
> -					   sizeof(intel_dp->dpcd)) &&
> -	    (intel_dp->dpcd[DP_DPCD_REV] != 0)) {
> -		return true;
> -	}
> +					   sizeof(intel_dp->dpcd) == 0))

Misplaced brace, isn't it? You're passing "sizeof(intel_dp->dpcd) == 0"
as length.

BR,
Jani.

> +		return false; /* aux transfer failed */
>  
> -	return false;
> +	if (intel_dp->dpcd[DP_DPCD_REV] == 0)
> +		return false; /* DPCD not present */
> +
> +	if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> +	      DP_DWN_STRM_PORT_PRESENT))
> +		return true; /* native DP sink */
> +
> +	if (intel_dp->dpcd[DP_DPCD_REV] == 0x10)
> +		return true; /* no per-port downstream info */
> +
> +	if (intel_dp_aux_native_read_retry(intel_dp, DP_DOWNSTREAM_PORT_0,
> +					   intel_dp->downstream_ports,
> +					   DP_MAX_DOWNSTREAM_PORTS) == 0)
> +		return false; /* downstream port status fetch failed */
> +
> +	return true;
>  }
>  
>  static void
> -- 
> 1.7.7.6
>
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