On 25/03/2019 12:37, Andrzej Hajda wrote:
> On 15.03.2019 10:54, Neil Armstrong wrote:
>> This patch is an attempt to limit HDMI 2.0 SCDC setup when :
>> - the SoC embeds an HDMI 1.4 only controller
>> - the EDID supports SCDC but not scrambling
>> - the EDID supports SCDC scrambling but not for low TMDS bit rates,
>> while only supporting low TMDS bit rates
>>
>> This to avoid communicating with the SCDC DDC slave uncessary, and
>> setting the DW-HDMI TMDS Scrambler setup when not supported by the
>> underlying hardware.
>>
>> Reported-by: Rob Herring <r...@kernel.org>
>> Fixes: 264fce6cc2c1 ("drm/bridge: dw-hdmi: Add SCDC and TMDS Scrambling
>> support")
>> Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
>> ---
>>
>> Rob,
>>
>> this patch should also solve your issue with your 11' display, could you
>> test it ?
>> If this works, I will focus on the underlying issue where the RK3399 SoC
>> freezes in your setup.
>>
>> Thanks,
>> Neil
>>
>> drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 34 ++++++++++++++++++++---
>> 1 file changed, 30 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index a63e5f0dae56..db761329a1e3 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -1037,6 +1037,31 @@ void dw_hdmi_phy_i2c_write(struct dw_hdmi *hdmi,
>> unsigned short data,
>> }
>> EXPORT_SYMBOL_GPL(dw_hdmi_phy_i2c_write);
>>
>> +/* Filter out invalid setups to avoid configuring SCDC and scrambling */
>> +static bool dw_hdmi_support_scdc(struct dw_hdmi *hdmi)
>> +{
>> + struct drm_display_info *display = &hdmi->connector.display_info;
>> +
>> + /* Completely disable SCDC support for older controllers */
>> + if (hdmi->version < 0x200a)
>> + return false;
>> +
>> + /* Disable if SCDC is not supported, or if an HF-VSDB block is absent */
>> + if (!display->hdmi.scdc.supported ||
>> + !display->hdmi.scdc.scrambling.supported)
>> + return false;
>> +
>> + /*
>> + * Disable if display only support low TMDS rates and scrambling
>> + * for low rates is not supported either
>> + */
>> + if (!display->hdmi.scdc.scrambling.low_rates &&
>> + display->max_tmds_clock <= 340000)
>> + return false;
>> +
>> + return true;
>> +}
>> +
>> /*
>> * HDMI2.0 Specifies the following procedure for High TMDS Bit Rates:
>> * - The Source shall suspend transmission of the TMDS clock and data
>> @@ -1055,7 +1080,7 @@ void dw_hdmi_set_high_tmds_clock_ratio(struct dw_hdmi
>> *hdmi)
>> unsigned long mtmdsclock = hdmi->hdmi_data.video_mode.mtmdsclock;
>>
>> /* Control for TMDS Bit Period/TMDS Clock-Period Ratio */
>> - if (hdmi->connector.display_info.hdmi.scdc.supported) {
>> + if (dw_hdmi_support_scdc(hdmi)) {
>> if (mtmdsclock > HDMI14_MAX_TMDSCLK)
>> drm_scdc_set_high_tmds_clock_ratio(hdmi->ddc, 1);
>> else
>> @@ -1579,8 +1604,9 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi,
>>
>> /* Set up HDMI_FC_INVIDCONF */
>> inv_val = (hdmi->hdmi_data.hdcp_enable ||
>> - vmode->mtmdsclock > HDMI14_MAX_TMDSCLK ||
>> - hdmi_info->scdc.scrambling.low_rates ?
>> + (dw_hdmi_support_scdc(hdmi) &&
>> + (vmode->mtmdsclock > HDMI14_MAX_TMDSCLK ||
>> + hdmi_info->scdc.scrambling.low_rates)) ?
>> HDMI_FC_INVIDCONF_HDCP_KEEPOUT_ACTIVE :
>> HDMI_FC_INVIDCONF_HDCP_KEEPOUT_INACTIVE);
>
>
> The condition is hard to read, but I have no idea atm how make it
> compact and pretty :)
I made my best to make it barely readable...
We may need to reword this condition since on the DW-HMI in the Allwinner
H6, this is no more needed for scrambling !
>
> Anyway:
>
> Reviewed-by: Andrzej Hajda <a.ha...@samsung.com>
>
>
> As I remember you can queue it to drm-misc, if not I can do it, just let
> me know.
I can and I'm queuing it right now, thanks for the review !
Neil
>
>
> --
> Regards
> Andrzej
>
>
>
>>
>> @@ -1646,7 +1672,7 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi,
>> }
>>
>> /* Scrambling Control */
>> - if (hdmi_info->scdc.supported) {
>> + if (dw_hdmi_support_scdc(hdmi)) {
>> if (vmode->mtmdsclock > HDMI14_MAX_TMDSCLK ||
>> hdmi_info->scdc.scrambling.low_rates) {
>> /*
>
>
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