On Thu, 2017-01-26 at 21:44 +0200, Jani Nikula wrote:
> Now that source rates are static and sink rates are updated whenever
> DPCD is updated, we can do and cache the intersection of them whenever
> sink rates are updated. This reduces code complexity, as we don't have
> to keep calling the functions to intersect. We also get rid of several
> common rates arrays on stack.
>
> Limiting the common rates by a max link rate can be done by picking the
> first N elements of the cached common rates.
>
> Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 66 ++++++++++++++++++++++------------------
> drivers/gpu/drm/i915/intel_drv.h | 3 ++
> 2 files changed, 40 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index f163391e61fa..7d3ff92000c3 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -283,17 +283,29 @@ static int intel_dp_find_rate(const int *rates, int len, int rate)
> return -1;
> }
>
> -static int intel_dp_common_rates(struct intel_dp *intel_dp,
> - int *common_rates)
> +static void intel_dp_set_common_rates(struct intel_dp *intel_dp)
> {
> - int max_rate = intel_dp->max_sink_link_rate;
> - int i, common_len;
> + WARN_ON(!intel_dp->num_source_rates || !intel_dp->num_sink_rates);
>
> - common_len = intersect_rates(intel_dp->source_rates,
> - intel_dp->num_source_rates,
> - intel_dp->sink_rates,
> - intel_dp->num_sink_rates,
> - common_rates);
> + intel_dp->num_common_rates = intersect_rates(intel_dp->source_rates,
> + intel_dp->num_source_rates,
> + intel_dp->sink_rates,
> + intel_dp->num_sink_rates,
> + intel_dp->common_rates);
Do we need to pass all these args given that all of them are now
available in intel_dp and intersect_rates() is not used anywhere else?
-DK
> +
> + /* Paranoia, there should always be something in common. */
> + if (WARN_ON(intel_dp->num_common_rates == 0)) {
> + intel_dp->common_rates[0] = default_rates[0];
> + intel_dp->num_common_rates = 1;
> + }
> +}
> +
> +/* get length of common rates potentially limited by max_rate */
> +static int intel_dp_common_len_rate_limit(struct intel_dp *intel_dp,
> + int max_rate)
> +{
> + const int *common_rates = intel_dp->common_rates;
> + int i, common_len = intel_dp->num_common_rates;
>
> /* Limit results by potentially reduced max rate */
> for (i = 0; i < common_len; i++) {
> @@ -304,25 +316,23 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
> return 0;
> }
>
> -static int intel_dp_link_rate_index(struct intel_dp *intel_dp,
> - int *common_rates, int link_rate)
> +static int intel_dp_link_rate_index(struct intel_dp *intel_dp, int link_rate)
> {
> int common_len;
>
> - common_len = intel_dp_common_rates(intel_dp, common_rates);
> + common_len = intel_dp_common_len_rate_limit(intel_dp,
> + intel_dp->max_sink_link_rate);
>
> - return intel_dp_find_rate(common_rates, common_len, link_rate);
> + return intel_dp_find_rate(intel_dp->common_rates, common_len, link_rate);
> }
>
> int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> int link_rate, uint8_t lane_count)
> {
> - int common_rates[DP_MAX_SUPPORTED_RATES];
> + const int *common_rates = intel_dp->common_rates;
> int link_rate_index;
>
> - link_rate_index = intel_dp_link_rate_index(intel_dp,
> - common_rates,
> - link_rate);
> + link_rate_index = intel_dp_link_rate_index(intel_dp, link_rate);
> if (link_rate_index > 0) {
> intel_dp->max_sink_link_rate = common_rates[link_rate_index - 1];
> intel_dp->max_sink_lane_count = lane_count;
> @@ -1509,8 +1519,6 @@ static void snprintf_int_array(char *str, size_t len,
>
> static void intel_dp_print_rates(struct intel_dp *intel_dp)
> {
> - int common_len;
> - int common_rates[DP_MAX_SUPPORTED_RATES];
> char str[128]; /* FIXME: too big for stack? */
>
> if ((drm_debug & DRM_UT_KMS) == 0)
> @@ -1524,8 +1532,8 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
> intel_dp->sink_rates, intel_dp->num_sink_rates);
> DRM_DEBUG_KMS("sink rates: %s\n", str);
>
> - common_len = intel_dp_common_rates(intel_dp, common_rates);
> - snprintf_int_array(str, sizeof(str), common_rates, common_len);
> + snprintf_int_array(str, sizeof(str),
> + intel_dp->common_rates, intel_dp->num_common_rates);
> DRM_DEBUG_KMS("common rates: %s\n", str);
> }
>
> @@ -1563,14 +1571,14 @@ bool intel_dp_read_desc(struct intel_dp *intel_dp)
> int
> intel_dp_max_link_rate(struct intel_dp *intel_dp)
> {
> - int rates[DP_MAX_SUPPORTED_RATES] = {};
> int len;
>
> - len = intel_dp_common_rates(intel_dp, rates);
> + len = intel_dp_common_len_rate_limit(intel_dp,
> + intel_dp->max_sink_link_rate);
> if (WARN_ON(len <= 0))
> return 162000;
>
> - return rates[len - 1];
> + return intel_dp->common_rates[len - 1];
> }
>
> int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
> @@ -1639,11 +1647,12 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> int link_rate_index;
> int bpp, mode_rate;
> int link_avail, link_clock;
> - int common_rates[DP_MAX_SUPPORTED_RATES] = {};
> + const int *common_rates = intel_dp->common_rates;
> int common_len;
> uint8_t link_bw, rate_select;
>
> - common_len = intel_dp_common_rates(intel_dp, common_rates);
> + common_len = intel_dp_common_len_rate_limit(intel_dp,
> + intel_dp->max_sink_link_rate);
>
> /* No common link rates between source and sink */
> WARN_ON(common_len <= 0);
> @@ -1681,7 +1690,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> /* Use values requested by Compliance Test Request */
> if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
> link_rate_index = intel_dp_link_rate_index(intel_dp,
> - common_rates,
> intel_dp->compliance.test_link_rate);
> if (link_rate_index >= 0)
> min_clock = max_clock = link_rate_index;
> @@ -3724,6 +3732,7 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
> } else {
> intel_dp_set_sink_rates(intel_dp);
> }
> + intel_dp_set_common_rates(intel_dp);
>
> return true;
> }
> @@ -3736,6 +3745,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> return false;
>
> intel_dp_set_sink_rates(intel_dp);
> + intel_dp_set_common_rates(intel_dp);
>
> if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
> &intel_dp->sink_count, 1) < 0)
> @@ -3958,7 +3968,6 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
> {
> int status = 0;
> int min_lane_count = 1;
> - int common_rates[DP_MAX_SUPPORTED_RATES] = {};
> int link_rate_index, test_link_rate;
> uint8_t test_lane_count, test_link_bw;
> /* (DP CTS 1.2)
> @@ -3987,7 +3996,6 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
> /* Validate the requested link rate */
> test_link_rate = drm_dp_bw_code_to_link_rate(test_link_bw);
> link_rate_index = intel_dp_link_rate_index(intel_dp,
> - common_rates,
> test_link_rate);
> if (link_rate_index < 0)
> return DP_TEST_NAK;
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index ae7259eda420..3578a7dd584a 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -936,6 +936,9 @@ struct intel_dp {
> /* sink rates as reported by DP_MAX_LINK_RATE/DP_SUPPORTED_LINK_RATES */
> int num_sink_rates;
> int sink_rates[DP_MAX_SUPPORTED_RATES];
> + /* intersection of source and sink rates */
> + int num_common_rates;
> + int common_rates[DP_MAX_SUPPORTED_RATES];
> /* Max lane count for the sink as per DPCD registers */
> uint8_t max_sink_lane_count;
> /* Max link BW for the sink as per DPCD registers */
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