[Intel-gfx] [PATCH] drm/i915: Detect virtual south bridge

[Robert Beckett]

On 02/09/2015 11:11, Daniel Vetter wrote:
> On Fri, Aug 28, 2015 at 01:10:22PM +0100, robert.beckett at intel.com wrote:
>> From: Robert Beckett <robert.beckett at intel.com>
>>
>> Virtualized systems often use a virtual P2X4 south bridge.
>> Detect this in intel_detect_pch and make a best guess as to which PCH
>> we should be using.
>>
>> This was seen on vmware esxi hypervisor. When passing the graphics device
>> through to a guest, it can not pass through the PCH. Instead it simulates
>> a P2X4 southbridge.
>>
>> Signed-off-by: Robert Beckett <robert.beckett at intel.com>
>
> What changed here compared to your earlier submission a day before?
> -Daniel

Nothing functional, just corrected the "[PATCH]" tag in the subject. My 
email client was doing weird things...

>
>> ---
>>   drivers/gpu/drm/i915/i915_drv.c |   30 ++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/i915/i915_drv.h |    1 +
>>   2 files changed, 31 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>> index ce3bd0c..8e158b3 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.c
>> +++ b/drivers/gpu/drm/i915/i915_drv.c
>> @@ -443,6 +443,34 @@ static const struct pci_device_id pciidlist[] = {		/* aka */
>>
>>   MODULE_DEVICE_TABLE(pci, pciidlist);
>>
>> +static enum intel_pch intel_virt_detect_pch(struct drm_device *dev)
>> +{
>> +	enum intel_pch ret = PCH_NOP;
>> +
>> +	/*
>> +	 * In a virtualized passthrough environment we can be in a
>> +	 * setup where the ISA bridge is not able to be passed through.
>> +	 * In this case, a south bridge can be emulated and we have to
>> +	 * make an educated guess as to which PCH is really there.
>> +	 */
>> +
>> +	if (IS_GEN5(dev)) {
>> +		ret = PCH_IBX;
>> +		DRM_DEBUG_KMS("Assuming Ibex Peak PCH\n");
>> +	} else if (IS_GEN6(dev) || IS_IVYBRIDGE(dev)) {
>> +		ret = PCH_CPT;
>> +		DRM_DEBUG_KMS("Assuming CouarPoint PCH\n");
>> +	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
>> +		ret = PCH_LPT;
>> +		DRM_DEBUG_KMS("Assuming LynxPoint PCH\n");
>> +	} else if (IS_SKYLAKE(dev)) {
>> +		ret = PCH_SPT;
>> +		DRM_DEBUG_KMS("Assuming SunrisePoint PCH\n");
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>   void intel_detect_pch(struct drm_device *dev)
>>   {
>>   	struct drm_i915_private *dev_priv = dev->dev_private;
>> @@ -503,6 +531,8 @@ void intel_detect_pch(struct drm_device *dev)
>>   				dev_priv->pch_type = PCH_SPT;
>>   				DRM_DEBUG_KMS("Found SunrisePoint LP PCH\n");
>>   				WARN_ON(!IS_SKYLAKE(dev));
>> +			} else if (id == INTEL_PCH_P2X_DEVICE_ID_TYPE) {
>> +				dev_priv->pch_type = intel_virt_detect_pch(dev);
>>   			} else
>>   				continue;
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 8c93845..6eb0230 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -2584,6 +2584,7 @@ struct drm_i915_cmd_table {
>>   #define INTEL_PCH_LPT_LP_DEVICE_ID_TYPE		0x9c00
>>   #define INTEL_PCH_SPT_DEVICE_ID_TYPE		0xA100
>>   #define INTEL_PCH_SPT_LP_DEVICE_ID_TYPE		0x9D00
>> +#define INTEL_PCH_P2X_DEVICE_ID_TYPE		0x7100
>>
>>   #define INTEL_PCH_TYPE(dev) (__I915__(dev)->pch_type)
>>   #define HAS_PCH_SPT(dev) (INTEL_PCH_TYPE(dev) == PCH_SPT)
>> --
>> 1.7.9.5
>>
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>