[PATCH v9 08/12] drm/i915: Read DP branch device SW revision

[Jim Bride]

On Fri, Sep 09, 2016 at 02:10:54PM +0300, Mika Kahola wrote:
> SW revision is mandatory field for DisplayPort branch
> devices. This is defined in DPCD register fields 0x50A
> and 0x50B.
> 
> v2: move drm_dp_ds_revision structure to be part of
>     drm_dp_link structure (Daniel)
> v3: remove dependency to drm_dp_helper but instead parse
>     DPCD and print SW revision info to dmesg (Ville)
> v4: commit message fix (Jim Bride)
> 
> Signed-off-by: Mika Kahola <mika.kahola at intel.com>

Reviewed-by: Jim Bride <jim.bride at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/intel_dp.c | 20 ++++++++++++++++++++
>  include/drm/drm_dp_helper.h     |  1 +
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index bb0417c..7428c72 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1438,6 +1438,25 @@ static void intel_dp_print_hw_revision(struct intel_dp *intel_dp)
>  	DRM_DEBUG_KMS("sink hw revision: %d.%d\n", (rev & 0xf0) >> 4, rev & 0xf);
>  }
>  
> +static void intel_dp_print_sw_revision(struct intel_dp *intel_dp)
> +{
> +	uint8_t rev[2];
> +	int len;
> +
> +	if ((drm_debug & DRM_UT_KMS) == 0)
> +		return;
> +
> +	if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> +	      DP_DWN_STRM_PORT_PRESENT))
> +		return;
> +
> +	len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_SW_REV, &rev, 2);
> +	if (len < 0)
> +		return;
> +
> +	DRM_DEBUG_KMS("sink sw revision: %d.%d\n", rev[0], rev[1]);
> +}
> +
>  static int rate_to_index(int find, const int *rates)
>  {
>  	int i = 0;
> @@ -4332,6 +4351,7 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
>  	intel_dp_probe_oui(intel_dp);
>  
>  	intel_dp_print_hw_revision(intel_dp);
> +	intel_dp_print_sw_revision(intel_dp);
>  
>  	intel_dp_configure_mst(intel_dp);
>  
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 19ac599..215202f 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -447,6 +447,7 @@
>  #define DP_BRANCH_OUI			    0x500
>  #define DP_BRANCH_ID                        0x503
>  #define DP_BRANCH_HW_REV                    0x509
> +#define DP_BRANCH_SW_REV                    0x50A
>  
>  #define DP_SET_POWER                        0x600
>  # define DP_SET_POWER_D0                    0x1
> -- 
> 2.7.4