On Mon, Oct 15, 2018 at 02:50:32PM -0700, Anusha Srivatsa wrote:
> Similar to DSC DPCD registers, let us cache
> FEC_CAPABLE register to avoid using stale
> values. With this we can avoid aux reads
> everytime and instead read the cached values.
>
> Suggested-by: Jani Nikula <jani.nik...@linux.intel.com>
> Cc: Jani Nikula <jani.nik...@linux.intel.com>
> Cc: Ville Syrjala <ville.syrj...@linux.intel.com>
> Cc: Manasi Navare <manasi.d.nav...@intel.com>
> Signed-off-by: Anusha Srivatsa <anusha.sriva...@intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 8 ++++++++
> drivers/gpu/drm/i915/intel_drv.h | 1 +
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index dcc5a207fcbd..8a0e0a0b26f6 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4163,8 +4163,10 @@ static void intel_dp_get_dsc_sink_cap(struct intel_dp
> *intel_dp)
> /*
> *Clear the cached register set to avoid using stale values
> * for the sinks that do not support DSC.
> + * Similarly, clear the cached FEC register.
> */
> memset(intel_dp->dsc_dpcd, 0, sizeof(intel_dp->dsc_dpcd));
> + memset(intel_dp->fec_dpcd, 0, sizeof(intel_dp->fec_dpcd));
Memset is an expensive opertaion for just a single value,
just set that to 0
>
> /* Cache the DSC DPCD if eDP or DP rev >= 1.4 */
> if (intel_dp->dpcd[DP_DPCD_REV] >= 0x14 ||
> @@ -4179,6 +4181,12 @@ static void intel_dp_get_dsc_sink_cap(struct intel_dp
> *intel_dp)
> (int)sizeof(intel_dp->dsc_dpcd),
> intel_dp->dsc_dpcd);
> }
> + /* FEC is supported only on DP 1.4 */
> + if (!intel_dp_is_edp(intel_dp) && intel_dp->dpcd[DP_DPCD_REV] >= 0x14) {
> + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_FEC_CAPABILITY,
> + intel_dp->fec_dpcd) < 0)
> + DRM_ERROR("Failed to read FEC DPCD register\n");
> + }
> }
>
> static bool
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index 7b4af8cba279..b87ea052c9ca 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1086,6 +1086,7 @@ struct intel_dp {
> uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
> uint8_t edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
> u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> + u8 fec_dpcd[1];
Why create an array for just 1 value, I think just a u8 fec_capable field
will suffice
Manasi
> /* source rates */
> int num_source_rates;
> const int *source_rates;
> --
> 2.17.1
>
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