[Intel-gfx] [PATCH 3/5] drm/i915/bxt: Added _DSM call to set HPD_CTL.

[Animesh Manna]

On 11/23/2016 11:47 PM, Ville Syrjälä wrote:
> On Wed, Nov 23, 2016 at 09:48:25PM +0530, Animesh Manna wrote:
>> _DSM is added to program HPD_CTL(0x1094) register
>> of PMC from i915 driver which will be called
>> based on driver feature flag. PMC hpd control register
>> programming will enable PMC to get hpd interrupt
>> during dc9.
>>
>> Signed-off-by: Animesh Manna <animesh.manna at intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_acpi.c | 44 ++++++++++++++++++++++++++++++++-------
>>   1 file changed, 37 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_acpi.c b/drivers/gpu/drm/i915/intel_acpi.c
>> index 8c878ab..15d3b84 100755
>> --- a/drivers/gpu/drm/i915/intel_acpi.c
>> +++ b/drivers/gpu/drm/i915/intel_acpi.c
>> @@ -10,6 +10,8 @@
>>   
>>   #define INTEL_DSM_REVISION_ID 1 /* For Calpella anyway... */
>>   #define INTEL_DSM_FN_PLATFORM_MUX_INFO 1 /* No args */
>> +#define INTEL_DSM_SET_HPD_WAKEUP 17
>> +#define HPD_WAKEUP_EN_VAL 0xFCF0
>>   
>>   static struct intel_dsm_priv {
>>   	acpi_handle dhandle;
>> @@ -118,6 +120,25 @@ static void intel_dsm_platform_mux_info(void)
>>   	ACPI_FREE(pkg);
>>   }
>>   
>> +static void intel_dsm_set_hpd_wakeup(u8 *guid)
>> +{
>> +	union acpi_object *obj;
>> +	union acpi_object argv4 = {
>> +		.integer.type = ACPI_TYPE_INTEGER,
>> +		.integer.value = HPD_WAKEUP_EN_VAL,
>> +	};
>> +
>> +	obj = acpi_evaluate_dsm_typed(intel_dsm_priv.dhandle, guid,
>> +			INTEL_DSM_REVISION_ID, INTEL_DSM_SET_HPD_WAKEUP,
>> +			&argv4, ACPI_TYPE_INTEGER);
>> +
>> +	if (!obj)
>> +		DRM_DEBUG_DRIVER("failed to evaluate _DSM\n");
>> +
>> +	ACPI_FREE(obj);
>> +}
>> +
>> +
>>   static bool intel_dsm_pci_probe(struct pci_dev *pdev)
>>   {
>>   	acpi_handle dhandle;
>> @@ -134,14 +155,23 @@ static bool intel_dsm_pci_probe(struct pci_dev *pdev)
>>   	else
>>   		guid = intel_dsm_guid;
>>   
>> -	if (!acpi_check_dsm(dhandle, guid, INTEL_DSM_REVISION_ID,
>> -			    1 << INTEL_DSM_FN_PLATFORM_MUX_INFO)) {
>> -		DRM_DEBUG_KMS("no _DSM method for intel device\n");
>> -		return false;
>> -	}
>> -
>>   	intel_dsm_priv.dhandle = dhandle;
>> -	intel_dsm_platform_mux_info();
>> +
>> +	if (acpi_check_dsm(dhandle, guid, INTEL_DSM_REVISION_ID,
>> +				1 << INTEL_DSM_FN_PLATFORM_MUX_INFO))
>> +		intel_dsm_platform_mux_info();
>> +	else
>> +		DRM_DEBUG_KMS("no _DSM method for mux-info\n");
>> +
>> +	/* Need to ensure vbt parsing is completed. */
> Eh?
There is a feature flag for oem to enable/disable HPD as wake feature in 
vbt and on the basis of that PMC_HPD_CTL register will be programmed.
So added a comment just to have that info captured in code-comment, for 
any concern let me know, will update accordingly.
>
>> +	if (dev_priv->vbt.hpd_wakeup_enabled &&
>> +		acpi_check_dsm(dhandle, guid, INTEL_DSM_REVISION_ID,
>> +				1 << INTEL_DSM_SET_HPD_WAKEUP))
>> +		intel_dsm_set_hpd_wakeup(guid);
> So we're permanently routing hpds to the pcu? Won't that mess up
> stuff like short pulse detection?
>
> I was expecting that we'd switch between the PCU and not during
> runtime suspend/resume.
Routing hpd to the pcu will only happen during S0ix. As per my 
understanding for both HDMI and DP we will be getting long pulse during 
hotplug at S0ix. So I think it will not mess up.
Correct me if I am missing something.

- Animesh
>
>> +	else {
>> +		dev_priv->vbt.hpd_wakeup_enabled = false;
>> +		DRM_DEBUG_KMS("no _DSM method for hpd-enabling\n");
>> +	}
>>   
>>   	return true;
>>   }
>> -- 
>> 1.9.1
>>
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