Re: [PATCH v2 5/6] drm/i915: enable scrambling

Sharma, Shashank
2017-02-07T16:05:00Z

Regards

Shashank

On 2/7/2017 3:51 PM, Jani Nikula wrote:
> On Mon, 06 Feb 2017, Shashank Sharma <shashank.sharma@intel.com> wrote:
>> Geminilake platform sports a native HDMI 2.0 controller, and is
>> capable of driving pixel-clocks upto 594Mhz. HDMI 2.0 spec
>> mendates scrambling for these higher clocks, for reduced RF footprint.
>>
>> This patch checks if the monitor supports scrambling, and if required,
>> enables it during the modeset.
> Throughout this series, but particularly in this patch, I'd prefer using
> the term "sink" instead of "monitor" everywhere. The HDMI specifications
> use source and sink almost exclusively.
>
> BR,
> Jani.
Sure, can be done.
- Shashank
>
>> V2: Addressed review comments from Ville:
>> - Do not track scrambling status in DRM layer, track somewhere in
>> driver like in intel_crtc_state.
>> - Don't talk to monitor at such a low layer, set monitor scrambling
>> in intel_enable_ddi() before enabling the port.
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
>> ---
>> drivers/gpu/drm/i915/i915_reg.h | 2 ++
>> drivers/gpu/drm/i915/intel_ddi.c | 26 +++++++++++++++
>> drivers/gpu/drm/i915/intel_drv.h | 11 ++++++
>> drivers/gpu/drm/i915/intel_hdmi.c | 70 +++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 109 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 495b789..cc85892 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -7807,6 +7807,8 @@ enum {
>> #define TRANS_DDI_EDP_INPUT_C_ONOFF (6<<12)
>> #define TRANS_DDI_DP_VC_PAYLOAD_ALLOC (1<<8)
>> #define TRANS_DDI_BFI_ENABLE (1<<4)
>> +#define TRANS_DDI_HIGH_TMDS_CHAR_RATE (1<<4)
>> +#define TRANS_DDI_HDMI_SCRAMBLING (1<<0)
>>
>> /* DisplayPort Transport Control */
>> #define _DP_TP_CTL_A 0x64040
>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
>> index 9a9a670..cc7e091 100644
>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>> @@ -1278,6 +1278,11 @@ void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
>> temp |= TRANS_DDI_MODE_SELECT_HDMI;
>> else
>> temp |= TRANS_DDI_MODE_SELECT_DVI;
>> +
>> + if (IS_GEMINILAKE(dev_priv))
>> + temp = intel_hdmi_handle_source_scrambling(
>> + intel_encoder,
>> + &intel_crtc->config->base.adjusted_mode, temp);
>> } else if (type == INTEL_OUTPUT_ANALOG) {
>> temp |= TRANS_DDI_MODE_SELECT_FDI;
>> temp |= (intel_crtc->config->fdi_lanes - 1) << 1;
>> @@ -1845,6 +1850,21 @@ static void intel_enable_ddi(struct intel_encoder *intel_encoder,
>> struct intel_digital_port *intel_dig_port =
>> enc_to_dig_port(encoder);
>>
>> + if (IS_GEMINILAKE(dev_priv)) {
>> + /*
>> + * GLK sports a native HDMI 2.0 controller. If required
>> + * clock rate is > 340 Mhz && scrambling is supported
>> + * by monitor, enable scrambling before enabling the
>> + * HDMI 2.0 port. The sink can choose to disable the
>> + * scrambling if it doesn't detect a scrambled within
>> + * 100 ms.
>> + */
>> + intel_hdmi_handle_monitor_scrambling(intel_encoder,
>> + conn_state->connector,
>> + intel_crtc->config,
>> + true);
>> + }
>> +
>> /* In HDMI/DVI mode, the port width, and swing/emphasis values
>> * are ignored so nothing special needs to be done besides
>> * enabling the port.
>> @@ -1885,6 +1905,12 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder,
>> intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);
>> }
>>
>> + if (type == INTEL_OUTPUT_HDMI) {
>> + intel_hdmi_handle_monitor_scrambling(intel_encoder,
>> + old_conn_state->connector,
>> + intel_crtc->config, false);
>> + }
>> +
>> if (type == INTEL_OUTPUT_EDP) {
>> struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>>
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> index 393f243..300353c 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -681,6 +681,9 @@ struct intel_crtc_state {
>>
>> /* Gamma mode programmed on the pipe */
>> uint32_t gamma_mode;
>> +
>> + /* HDMI scrambling status (monitor) */
>> + bool scrambling;
>> };
>>
>> struct vlv_wm_state {
>> @@ -1588,6 +1591,14 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>> bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>> struct intel_crtc_state *pipe_config,
>> struct drm_connector_state *conn_state);
>> +uint32_t
>> +intel_hdmi_handle_source_scrambling(struct intel_encoder *intel_encoder,
>> + struct drm_display_mode *mode,
>> + uint32_t config);
>> +void intel_hdmi_handle_monitor_scrambling(struct intel_encoder *intel_encoder,
>> + struct drm_connector *connector,
>> + struct intel_crtc_state *config,
>> + bool enable);
>> void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
>>
>>
>> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
>> index ebae2bd..41d3309 100644
>> --- a/drivers/gpu/drm/i915/intel_hdmi.c
>> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
>> @@ -34,6 +34,7 @@
>> #include <drm/drm_atomic_helper.h>
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_edid.h>
>> +#include <drm/drm_scdc_helper.h>
>> #include "intel_drv.h"
>> #include <drm/i915_drm.h>
>> #include <drm/intel_lpe_audio.h>
>> @@ -1795,6 +1796,75 @@ static void intel_hdmi_destroy(struct drm_connector *connector)
>> intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
>> }
>>
>> +void intel_hdmi_handle_monitor_scrambling(struct intel_encoder *intel_encoder,
>> + struct drm_connector *connector,
>> + struct intel_crtc_state *config,
>> + bool enable)
>> +{
>> + struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&intel_encoder->base);
>> + struct drm_scdc *scdc = &connector->display_info.hdmi.scdc;
>> + struct drm_scrambling *scrambling = &scdc->scrambling;
>> + struct drm_display_mode *mode = &config->base.adjusted_mode;
>> + struct drm_i915_private *dev_priv = connector->dev->dev_private;
>> + struct i2c_adapter *adptr = intel_gmbus_get_adapter(dev_priv,
>> + intel_hdmi->ddc_bus);
>> +
>> + if (!scrambling->supported)
>> + return;
>> +
>> + DRM_DEBUG_KMS("Setting monitor scrambling for enc:%s connector:%s\n",
>> + intel_encoder->base.name, connector->name);
>> +
>> + /* Enable monitor scrambling */
>> + if (enable) {
>> + if (mode->clock > 340000 || scrambling->low_rates) {
>> + config->scrambling = drm_scdc_enable_scrambling(adptr);
>> + if (!config->scrambling)
>> + DRM_ERROR("Can't enable monitor scrambling\n");
>> + }
>> + return;
>> + }
>> +
>> + /* Disable monitor scrambling */
>> + if (config->scrambling) {
>> + config->scrambling = !(drm_scdc_disable_scrambling(adptr));
>> + if (config->scrambling)
>> + DRM_ERROR("Can't disable monitor scrambling\n");
>> + }
>> +
>> +}
>> +
>> +uint32_t
>> +intel_hdmi_handle_source_scrambling(struct intel_encoder *intel_encoder,
>> + struct drm_display_mode *mode, uint32_t hdmi_config)
>> +{
>> + struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&intel_encoder->base);
>> + struct drm_connector *connector = &intel_hdmi->attached_connector->base;
>> + struct drm_hdmi_info *hdmi_info = &connector->display_info.hdmi;
>> + struct drm_scrambling *scrambling = &hdmi_info->scdc.scrambling;
>> +
>> + DRM_DEBUG_KMS("Setting scrambling for enc:%s connector:%s\n",
>> + intel_encoder->base.name, connector->name);
>> +
>> + hdmi_config &= ~TRANS_DDI_HDMI_SCRAMBLING;
>> + hdmi_config &= ~TRANS_DDI_HIGH_TMDS_CHAR_RATE;
>> +
>> + if (mode->clock <= 340000) {
>> + /* Few sinks support scrambling at rate < 340 MHz too */
>> + if (scrambling->low_rates)
>> + hdmi_config |= TRANS_DDI_HDMI_SCRAMBLING;
>> + return hdmi_config;
>> + }
>> +
>> + /* Scrambling or not, if clock > 340 MHz, set high char rate */
>> + hdmi_config |= TRANS_DDI_HIGH_TMDS_CHAR_RATE;
>> +
>> + if (scrambling->supported)
>> + hdmi_config |= TRANS_DDI_HDMI_SCRAMBLING;
>> +
>> + return hdmi_config;
>> +}
>> +
>> static u8 intel_hdmi_ddc_pin(struct drm_i915_private *dev_priv,
>> enum port port)
>> {