[Intel-gfx] [PATCH v5 4/6] drm/edid: detect SCDC support in HF-VSDB
Sharma, Shashank
shashank.sharma at intel.com
Thu Mar 2 02:37:11 UTC 2017
Regards
Shashank
On 3/1/2017 8:28 PM, Ville Syrjälä wrote:
> On Tue, Feb 28, 2017 at 02:09:08PM +0530, Shashank Sharma wrote:
>> This patch does following:
>> - Adds a new structure (drm_hdmi_info) in drm_display_info.
>> This structure will be used to save and indicate if sink
>> supports advanced HDMI 2.0 features
>> - Adds another structure drm_scdc within drm_hdmi_info, to
>> reflect scdc support and capabilities in connected HDMI 2.0 sink.
>> - Checks the HF-VSDB block for presence of SCDC, and marks it
>> in scdc structure
>> - If SCDC is present, checks if sink is capable of generating
>> SCDC read request, and marks it in scdc structure.
>>
>> V2: Addressed review comments
>> Thierry:
>> - Fix typos in commit message and make abbreviation consistent
>> across the commit message.
>> - Change structure object name from hdmi_info -> hdmi
>> - Fix typos and abbreviations in description of structure drm_hdmi_info
>> end the description with a full stop.
>> - Create a structure drm_scdc, and keep all information related to SCDC
>> register set (supported, read request supported) etc in it.
>>
>> Ville:
>> - Change rr -> read_request
>> - Call drm_detect_scrambling function drm_parse_hf_vsdb so that all
>> of HF-VSDB parsing can be kept in same function, in incremental
>> patches.
>>
>> V3: Rebase.
>> V4: Rebase.
>> V5: Rebase.
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>> Reviewed-by: Thierry Reding <treding at nvidia.com>
>> ---
>> drivers/gpu/drm/drm_edid.c | 33 +++++++++++-
>> drivers/gpu/drm/drm_scdc_helper.c | 111 ++++++++++++++++++++++++++++++++++++++
>> include/drm/drm_connector.h | 19 +++++++
>> include/drm/drm_edid.h | 6 ++-
>> include/drm/drm_scdc_helper.h | 27 ++++++++++
>> 5 files changed, 194 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 0881108..e84c5ab 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -37,6 +37,7 @@
>> #include <drm/drm_edid.h>
>> #include <drm/drm_encoder.h>
>> #include <drm/drm_displayid.h>
>> +#include <drm/drm_scdc_helper.h>
>>
>> #include "drm_crtc_internal.h"
>>
>> @@ -3817,13 +3818,43 @@ enum hdmi_quantization_range
>> static void drm_parse_hdmi_forum_vsdb(struct drm_connector *connector,
>> const u8 *hf_vsdb)
>> {
>> - struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
>> + struct drm_display_info *display = &connector->display_info;
>> + struct drm_hdmi_info *hdmi = &display->hdmi;
>>
>> if (hf_vsdb[6] & 0x80) {
>> hdmi->scdc.supported = true;
>> if (hf_vsdb[6] & 0x40)
>> hdmi->scdc.read_request = true;
>> }
>> +
>> + /*
>> + * All HDMI 2.0 monitors must support scrambling at rates > 340 MHz.
>> + * And as per the spec, three factors confirm this:
>> + * * Availability of a HF-VSDB block in EDID (check)
>> + * * Non zero Max_TMDS_Char_Rate filed in HF-VSDB (let's check)
>> + * * SCDC support available (let's check)
>> + * Lets check it out.
>> + */
>> +
>> + if (hf_vsdb[5]) {
>> + /* max clock is 5000 KHz times block value */
>> + u32 max_tmds_clock = hf_vsdb[5] * 5000;
>> + struct drm_scdc *scdc = &hdmi->scdc;
>> +
>> + if (max_tmds_clock > 340000) {
>> + display->max_tmds_clock = max_tmds_clock;
>> + DRM_DEBUG_KMS("HF-VSDB: max TMDS clock %d kHz\n",
>> + display->max_tmds_clock);
>> + }
>> +
>> + if (scdc->supported) {
>> + scdc->scrambling.supported = true;
>> +
>> + /* Few sinks support scrambling for cloks < 340M */
>> + if ((hf_vsdb[6] & 0x8))
>> + scdc->scrambling.low_rates = true;
>> + }
>> + }
>> }
>>
>> static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
>> diff --git a/drivers/gpu/drm/drm_scdc_helper.c b/drivers/gpu/drm/drm_scdc_helper.c
>> index c2dd33f..180a7cd 100644
>> --- a/drivers/gpu/drm/drm_scdc_helper.c
>> +++ b/drivers/gpu/drm/drm_scdc_helper.c
>> @@ -22,8 +22,10 @@
>> */
>>
>> #include <linux/slab.h>
>> +#include <linux/delay.h>
>>
>> #include <drm/drm_scdc_helper.h>
>> +#include <drm/drmP.h>
>>
>> /**
>> * DOC: scdc helpers
>> @@ -121,3 +123,112 @@ ssize_t drm_scdc_write(struct i2c_adapter *adapter, u8 offset,
>> return 0;
>> }
>> EXPORT_SYMBOL(drm_scdc_write);
>> +
>> +/**
>> + * drm_scdc_check_scrambling_status - what is status of scrambling?
>> + * @adapter: I2C adapter for DDC channel
>> + *
>> + * Reads the scrambler status over SCDC, and checks the
>> + * scrambling status.
>> + *
>> + * Returns:
>> + * True if the scrambling is enabled, false otherwise.
>> + */
>> +
>> +bool drm_scdc_get_scrambling_status(struct i2c_adapter *adapter)
>> +{
>> + u8 status;
>> + int ret;
>> +
>> + ret = drm_scdc_readb(adapter, SCDC_SCRAMBLER_STATUS, &status);
>> + if (ret < 0) {
>> + DRM_ERROR("Failed to read scrambling status, error %d\n", ret);
>> + return false;
>> + }
>> +
>> + return status & SCDC_SCRAMBLING_STATUS;
>> +}
>> +EXPORT_SYMBOL(drm_scdc_get_scrambling_status);
>> +
>> +/**
>> + * drm_scdc_set_scrambling - enable scrambling
>> + * @adapter: I2C adapter for DDC channel
>> + * @enable: bool to indicate if scrambling is to be enabled/disabled
>> + *
>> + * Writes the TMDS config register over SCDC channel, and:
>> + * enables scrambling when enable = 1
>> + * disables scrambling when enable = 0
>> + *
>> + * Returns:
>> + * True if scrambling is set/reset successfully, false otherwise.
>> + */
>> +
>> +bool drm_scdc_set_scrambling(struct i2c_adapter *adapter, bool enable)
>> +{
>> + u8 config;
>> + int ret;
>> +
>> + ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);
>> + if (ret < 0) {
>> + DRM_ERROR("Failed to read tmds config, err=%d\n", ret);
>> + return false;
>> + }
>> +
>> + if (enable)
>> + config |= SCDC_SCRAMBLING_ENABLE;
>> + else
>> + config &= ~SCDC_SCRAMBLING_ENABLE;
>> +
>> + ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config);
>> + if (ret < 0) {
>> + DRM_ERROR("Failed to enable scrambling, error %d\n", ret);
>> + return false;
>> + }
>> +
>> + return true;
>> +}
>> +EXPORT_SYMBOL(drm_scdc_set_scrambling);
>> +
>> +/**
>> + * drm_scdc_set_high_tmds_clock_ratio - set TMDS clock ratio
>> + * @adapter: I2C adapter for DDC channel
>> + * @set: ret or reset the high clock ratio
>> + *
>> + * Writes to the TMDS config register over SCDC channel, and:
>> + * sets TMDS clock ratio to 1/40 when set = 1
>> + * sets TMDS clock ratio to 1/10 when set = 0
> The 1/10 and 1/40 ratios confuse me a little since we never really deal
> with the bitrate in the driver. Instead we always deal with either pixel
> clock, character clock or TMDS clock (well prior to this TMDS clock ==
> character clock). So the factor 10 never enters the picture elsewhere.
> So I would prefer to specify these in those terms as well.
Ok, I will add comments for pixel clock as well
> An enum for the ratios might also help in making this a bit less
> cryptic.
Humm, not sure how helpful will be an enum, as thats only used in case
of pixelclock>340
asso, only two entries 1/40 and 1/10, but let me see if I can do that.
>> + *
>> + * Returns:
>> + * True if write is successful, false otherwise.
>> + */
>> +bool drm_scdc_set_high_tmds_clock_ratio(struct i2c_adapter *adapter, bool set)
>> +{
>> + u8 config;
>> + int ret;
>> +
>> + ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);
>> + if (ret < 0) {
>> + DRM_ERROR("Failed to read tmds config, err=%d\n", ret);
>> + return false;
>> + }
>> +
>> + if (set)
>> + config |= SCDC_TMDS_BIT_CLOCK_RATIO_BY_40;
>> + else
>> + config &= ~SCDC_TMDS_BIT_CLOCK_RATIO_BY_40;
>> +
>> + ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config);
>> + if (ret < 0) {
>> + DRM_ERROR("Failed to set TMDS clock ratio, error %d\n", ret);
>> + return false;
>> + }
>> +
>> + /*
>> + * The spec says that a source should wait minimum 1ms and maximum
>> + * 100ms after writing the TMDS config for clock ratio. Lets allow a
>> + * wait of upto 2ms here.
>> + */
>> + usleep_range(1000, 2000);
>> + return true;
>> +}
>> +EXPORT_SYMBOL(drm_scdc_set_high_tmds_clock_ratio);
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index 6d5304e..78618308 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -90,6 +90,20 @@ enum subpixel_order {
>>
>> };
>>
>> +/**
>> + * struct drm_scrambling: sink's scrambling support.
>> + */
>> +struct drm_scrambling {
>> + /**
>> + * @supported: scrambling supported for rates > 340 Mhz.
>> + */
>> + bool supported;
>> + /**
>> + * @low_rates: scrambling supported for rates <= 340 Mhz.
>> + */
>> + bool low_rates;
>> +};
>> +
>> /*
>> * struct drm_scdc - Information about scdc capabilities of a HDMI 2.0 sink
>> *
>> @@ -105,8 +119,13 @@ struct drm_scdc {
>> * @read_request: sink is capable of generating scdc read request.
>> */
>> bool read_request;
>> + /**
>> + * @scrambling: sink's scrambling capabilities
>> + */
>> + struct drm_scrambling scrambling;
>> };
>>
>> +
>> /**
>> * struct drm_hdmi_info - runtime information about the connected HDMI sink
>> *
>> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
>> index 3ead84d..f4a91e0 100644
>> --- a/include/drm/drm_edid.h
>> +++ b/include/drm/drm_edid.h
>> @@ -476,5 +476,9 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name,
>> struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
>> int hsize, int vsize, int fresh,
>> bool rb);
>> -
>> +bool drm_enable_scrambling(struct drm_connector *connector,
>> + struct i2c_adapter *adapter, bool force);
>> +bool drm_disable_scrambling(struct drm_connector *connector,
>> + struct i2c_adapter *adapter, bool force);
>> +bool drm_check_scrambling_status(struct i2c_adapter *adapter);
> Old leftovers?
Oops, my bad.
>> #endif /* __DRM_EDID_H__ */
>> diff --git a/include/drm/drm_scdc_helper.h b/include/drm/drm_scdc_helper.h
>> index 9c52deb..ab6bcfb 100644
>> --- a/include/drm/drm_scdc_helper.h
>> +++ b/include/drm/drm_scdc_helper.h
>> @@ -129,4 +129,31 @@ static inline int drm_scdc_writeb(struct i2c_adapter *adapter, u8 offset,
>> return drm_scdc_write(adapter, offset, &value, sizeof(value));
>> }
>>
>> +/**
>> + * drm_scdc_set_scrambling - enable scrambling
>> + * @adapter: I2C adapter for DDC channel
>> + * @enable: bool to indicate if scrambling is to be enabled/disabled
>> + *
>> + * Writes the TMDS config register over SCDC channel, and:
>> + * enables scrambling when enable = 1
>> + * disables scrambling when enable = 0
>> + *
>> + * Returns:
>> + * True if scrambling is set/reset successfully, false otherwise.
>> + */
>> +bool drm_scdc_set_scrambling(struct i2c_adapter *adapter, bool enable);
>> +
>> +/**
>> + * drm_scdc_set_high_tmds_clock_ratio - set TMDS clock ratio
>> + * @adapter: I2C adapter for DDC channel
>> + * @set: ret or reset the high clock ratio
>> + *
>> + * Writes to the TMDS config register over SCDC channel, and:
>> + * sets TMDS clock ratio to 1/40 when set = 1
>> + * sets TMDS clock ratio to 1/10 when set = 0
>> + *
>> + * Returns:
>> + * True if write is successful, false otherwise.
>> + */
>> +bool drm_scdc_set_high_tmds_clock_ratio(struct i2c_adapter *adapter, bool set);
>> #endif
>> --
>> 1.9.1
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