[Intel-gfx] [PATCH V2] drm/i915/glk: Add Quirk for GLK NUC HDMI port issues.

[Clint Taylor]

On 06/25/2018 03:33 AM, Imre Deak wrote:
> On Wed, Jun 13, 2018 at 02:48:49PM -0700, clinton.a.taylor at intel.com wrote:
>> From: Clint Taylor <clinton.a.taylor at intel.com>
>>
>> On GLK NUC platforms the HDMI retiming buffer needs additional disabled
>> time to correctly sync to a faster incoming signal.
>>
>> When measured on a scope the highspeed lines of the HDMI clock turn off
>>   for ~400uS during a normal resolution change. The HDMI retimer on the
>>   GLK NUC appears to require at least a full frame of quiet time before a
>> new faster clock can be correctly sync'd. The worst case scenario appears
>> to be 23.98Hz modes which requires a wait of 41.25ms. Add a quirk to the
>> driver for GLK NUC that waits 42ms.
>>
>> V2: Add more devices to the quirk list
>>
>> Cc: Imre Deak <imre.deak at intel.com>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105887
>> Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_drv.h      |  1 +
>>   drivers/gpu/drm/i915/intel_ddi.c     |  8 ++++++++
>>   drivers/gpu/drm/i915/intel_display.c | 19 +++++++++++++++++++
>>   3 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index be8c2f0..da196b4 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -656,6 +656,7 @@ enum intel_sbi_destination {
>>   #define QUIRK_BACKLIGHT_PRESENT (1<<3)
>>   #define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
>>   #define QUIRK_INCREASE_T12_DELAY (1<<6)
>> +#define QUIRK_INCREASE_DDI_DISABLED_TIME (1<<7)
>>   
>>   struct intel_fbdev;
>>   struct intel_fbc_work;
>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
>> index ca73387..bc3d012 100644
>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>> @@ -1791,6 +1791,9 @@ void intel_ddi_enable_transcoder_func(const struct intel_crtc_state *crtc_state)
>>   	I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
>>   }
>>   
>> +/* Quirk time computed based on 24fps frame time of 41.25ms */
>> +#define DDI_DISABLED_QUIRK_TIME 42
>> +
>>   void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
>>   				       enum transcoder cpu_transcoder)
>>   {
>> @@ -1800,6 +1803,11 @@ void intel_ddi_disable_transcoder_func(struct drm_i915_private *dev_priv,
>>   	val &= ~(TRANS_DDI_FUNC_ENABLE | TRANS_DDI_PORT_MASK | TRANS_DDI_DP_VC_PAYLOAD_ALLOC);
>>   	val |= TRANS_DDI_PORT_NONE;
>>   	I915_WRITE(reg, val);
>> +
>> +	if (dev_priv->quirks & QUIRK_INCREASE_DDI_DISABLED_TIME) {
>> +		msleep(DDI_DISABLED_QUIRK_TIME);
>> +		DRM_DEBUG_KMS("Quirk Increase DDI disabled time\n");
> No need for the define or the debug message here imo. msleep() can be
> inaccurate (even sleeping less than expected), so I'd use a bigger
> margin, sleeping say 100ms.

Easy to do and I can submit v3.

>
> If the problem is with the HDMI retimer chip, we should limit the quirk
> to HDMI outputs.
Output type is not available in intel_disable_ddi() and I would prefer 
not to change the interface only for the quirk. I could move the quirk 
execution up a level to haswell_crtc_disable() and detect the 
old_crtc_state->type before executing the quirk. However, the quirk is 
only being detected for certain boards that only have HDMI outputs. 
Unless more boards are added to the quirk_list[] we really don't need 
logic to detect HDMI outputs.

-Clint

>> +	}
>>   }
>>   
>>   int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 8251e18..40e0306 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -14749,6 +14749,17 @@ static void quirk_increase_t12_delay(struct drm_device *dev)
>>   	DRM_INFO("Applying T12 delay quirk\n");
>>   }
>>   
>> +/* GeminiLake NUC HDMI outputs require additional off time
>> + * this allows the onboard retimer to correctly sync to signal
>> + */
>> +static void quirk_increase_ddi_disabled_time(struct drm_device *dev)
>> +{
>> +	struct drm_i915_private *dev_priv = to_i915(dev);
>> +
>> +	dev_priv->quirks |= QUIRK_INCREASE_DDI_DISABLED_TIME;
>> +	DRM_INFO("Applying Increase DDI Disabled quirk\n");
>> +}
>> +
>>   struct intel_quirk {
>>   	int device;
>>   	int subsystem_vendor;
>> @@ -14835,6 +14846,14 @@ static int intel_dmi_reverse_brightness(const struct dmi_system_id *id)
>>   
>>   	/* Toshiba Satellite P50-C-18C */
>>   	{ 0x191B, 0x1179, 0xF840, quirk_increase_t12_delay },
>> +
>> +	/* GeminiLake NUC */
>> +	{ 0x3185, 0x8086, 0x2072, quirk_increase_ddi_disabled_time },
>> +	{ 0x3184, 0x8086, 0x2072, quirk_increase_ddi_disabled_time },
>> +	/* ASRock ITX*/
>> +	{ 0x3185, 0x1849, 0x2212, quirk_increase_ddi_disabled_time },
>> +	{ 0x3184, 0x1849, 0x2212, quirk_increase_ddi_disabled_time },
>> +
> Extra w/s. A quirk list looks ok for now since we can't identify the
> retimer chip in any other way.
>
>>   };
>>   
>>   static void intel_init_quirks(struct drm_device *dev)
>> -- 
>> 1.9.1
>>