drivers/gpu/drm/i915/intel_pch.c - linux - Git at Google

 // SPDX-License-Identifier: MIT
 /*
  * Copyright 2019 Intel Corporation.
  */

 #include "i915_drv.h"
 #include "intel_pch.h"

 /* Map PCH device id to PCH type, or PCH_NONE if unknown. */
 static enum intel_pch
 intel_pch_type(const struct drm_i915_private *dev_priv, unsigned short id)
 {
 	switch (id) {
 	case INTEL_PCH_IBX_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Ibex Peak PCH\n");
 		drm_WARN_ON(&dev_priv->drm, !IS_GEN(dev_priv, 5));
 		return PCH_IBX;
 	case INTEL_PCH_CPT_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found CougarPoint PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_GEN(dev_priv, 6) && !IS_IVYBRIDGE(dev_priv));
 		return PCH_CPT;
 	case INTEL_PCH_PPT_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found PantherPoint PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_GEN(dev_priv, 6) && !IS_IVYBRIDGE(dev_priv));
 		/* PantherPoint is CPT compatible */
 		return PCH_CPT;
 	case INTEL_PCH_LPT_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found LynxPoint PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
 		drm_WARN_ON(&dev_priv->drm,
 			    IS_HSW_ULT(dev_priv) || IS_BDW_ULT(dev_priv));
 		return PCH_LPT;
 	case INTEL_PCH_LPT_LP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found LynxPoint LP PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
 		return PCH_LPT;
 	case INTEL_PCH_WPT_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found WildcatPoint PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
 		drm_WARN_ON(&dev_priv->drm,
 			    IS_HSW_ULT(dev_priv) || IS_BDW_ULT(dev_priv));
 		/* WildcatPoint is LPT compatible */
 		return PCH_LPT;
 	case INTEL_PCH_WPT_LP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found WildcatPoint LP PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
 		/* WildcatPoint is LPT compatible */
 		return PCH_LPT;
 	case INTEL_PCH_SPT_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found SunrisePoint PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv));
 		return PCH_SPT;
 	case INTEL_PCH_SPT_LP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found SunrisePoint LP PCH\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_SKYLAKE(dev_priv) &&
 			    !IS_KABYLAKE(dev_priv) &&
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv));
 		return PCH_SPT;
 	case INTEL_PCH_KBP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Kaby Lake PCH (KBP)\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_SKYLAKE(dev_priv) &&
 			    !IS_KABYLAKE(dev_priv) &&
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv));
 		/* KBP is SPT compatible */
 		return PCH_SPT;
 	case INTEL_PCH_CNP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Cannon Lake PCH (CNP)\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_CANNONLAKE(dev_priv) &&
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv));
 		return PCH_CNP;
 	case INTEL_PCH_CNP_LP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm,
 			    "Found Cannon Lake LP PCH (CNP-LP)\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_CANNONLAKE(dev_priv) &&
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv));
 		return PCH_CNP;
 	case INTEL_PCH_CMP_DEVICE_ID_TYPE:
 	case INTEL_PCH_CMP2_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Comet Lake PCH (CMP)\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv) &&
 			    !IS_ROCKETLAKE(dev_priv));
 		/* CometPoint is CNP Compatible */
 		return PCH_CNP;
 	case INTEL_PCH_CMP_V_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Comet Lake V PCH (CMP-V)\n");
 		drm_WARN_ON(&dev_priv->drm,
 			    !IS_COFFEELAKE(dev_priv) &&
 			    !IS_COMETLAKE(dev_priv));
 		/* Comet Lake V PCH is based on KBP, which is SPT compatible */
 		return PCH_SPT;
 	case INTEL_PCH_ICP_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Ice Lake PCH\n");
 		drm_WARN_ON(&dev_priv->drm, !IS_ICELAKE(dev_priv));
 		return PCH_ICP;
 	case INTEL_PCH_MCC_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Mule Creek Canyon PCH\n");
 		drm_WARN_ON(&dev_priv->drm, !IS_JSL_EHL(dev_priv));
 		return PCH_MCC;
 	case INTEL_PCH_TGP_DEVICE_ID_TYPE:
 	case INTEL_PCH_TGP2_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Tiger Lake LP PCH\n");
 		drm_WARN_ON(&dev_priv->drm, !IS_TIGERLAKE(dev_priv) &&
 			    !IS_ROCKETLAKE(dev_priv));
 		return PCH_TGP;
 	case INTEL_PCH_JSP_DEVICE_ID_TYPE:
 	case INTEL_PCH_JSP2_DEVICE_ID_TYPE:
 		drm_dbg_kms(&dev_priv->drm, "Found Jasper Lake PCH\n");
 		drm_WARN_ON(&dev_priv->drm, !IS_JSL_EHL(dev_priv));
 		return PCH_JSP;
 	default:
 		return PCH_NONE;
 	}
 }

 static bool intel_is_virt_pch(unsigned short id,
 			      unsigned short svendor, unsigned short sdevice)
 {
 	return (id == INTEL_PCH_P2X_DEVICE_ID_TYPE ||
 		id == INTEL_PCH_P3X_DEVICE_ID_TYPE ||
 		(id == INTEL_PCH_QEMU_DEVICE_ID_TYPE &&
 		 svendor == PCI_SUBVENDOR_ID_REDHAT_QUMRANET &&
 		 sdevice == PCI_SUBDEVICE_ID_QEMU));
 }

 static unsigned short
 intel_virt_detect_pch(const struct drm_i915_private *dev_priv)
 {
 	unsigned short id = 0;

 	/*
 	 * 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_TIGERLAKE(dev_priv) || IS_ROCKETLAKE(dev_priv))
 		id = INTEL_PCH_TGP_DEVICE_ID_TYPE;
 	else if (IS_JSL_EHL(dev_priv))
 		id = INTEL_PCH_MCC_DEVICE_ID_TYPE;
 	else if (IS_ICELAKE(dev_priv))
 		id = INTEL_PCH_ICP_DEVICE_ID_TYPE;
 	else if (IS_CANNONLAKE(dev_priv) ||
 		 IS_COFFEELAKE(dev_priv) ||
 		 IS_COMETLAKE(dev_priv))
 		id = INTEL_PCH_CNP_DEVICE_ID_TYPE;
 	else if (IS_KABYLAKE(dev_priv) || IS_SKYLAKE(dev_priv))
 		id = INTEL_PCH_SPT_DEVICE_ID_TYPE;
 	else if (IS_HSW_ULT(dev_priv) || IS_BDW_ULT(dev_priv))
 		id = INTEL_PCH_LPT_LP_DEVICE_ID_TYPE;
 	else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
 		id = INTEL_PCH_LPT_DEVICE_ID_TYPE;
 	else if (IS_GEN(dev_priv, 6) || IS_IVYBRIDGE(dev_priv))
 		id = INTEL_PCH_CPT_DEVICE_ID_TYPE;
 	else if (IS_GEN(dev_priv, 5))
 		id = INTEL_PCH_IBX_DEVICE_ID_TYPE;

 	if (id)
 		drm_dbg_kms(&dev_priv->drm, "Assuming PCH ID %04x\n", id);
 	else
 		drm_dbg_kms(&dev_priv->drm, "Assuming no PCH\n");

 	return id;
 }

 void intel_detect_pch(struct drm_i915_private *dev_priv)
 {
 	struct pci_dev *pch = NULL;

 	/* DG1 has south engine display on the same PCI device */
 	if (IS_DG1(dev_priv)) {
 		dev_priv->pch_type = PCH_DG1;
 		return;
 	}

 	/*
 	 * The reason to probe ISA bridge instead of Dev31:Fun0 is to
 	 * make graphics device passthrough work easy for VMM, that only
 	 * need to expose ISA bridge to let driver know the real hardware
 	 * underneath. This is a requirement from virtualization team.
 	 *
 	 * In some virtualized environments (e.g. XEN), there is irrelevant
 	 * ISA bridge in the system. To work reliably, we should scan trhough
 	 * all the ISA bridge devices and check for the first match, instead
 	 * of only checking the first one.
 	 */
 	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
 		unsigned short id;
 		enum intel_pch pch_type;

 		if (pch->vendor != PCI_VENDOR_ID_INTEL)
 			continue;

 		id = pch->device & INTEL_PCH_DEVICE_ID_MASK;

 		pch_type = intel_pch_type(dev_priv, id);
 		if (pch_type != PCH_NONE) {
 			dev_priv->pch_type = pch_type;
 			dev_priv->pch_id = id;
 			break;
 		} else if (intel_is_virt_pch(id, pch->subsystem_vendor,
 					     pch->subsystem_device)) {
 			id = intel_virt_detect_pch(dev_priv);
 			pch_type = intel_pch_type(dev_priv, id);

 			/* Sanity check virtual PCH id */
 			if (drm_WARN_ON(&dev_priv->drm,
 					id && pch_type == PCH_NONE))
 				id = 0;

 			dev_priv->pch_type = pch_type;
 			dev_priv->pch_id = id;
 			break;
 		}
 	}

 	/*
 	 * Use PCH_NOP (PCH but no South Display) for PCH platforms without
 	 * display.
 	 */
 	if (pch && !HAS_DISPLAY(dev_priv)) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "Display disabled, reverting to NOP PCH\n");
 		dev_priv->pch_type = PCH_NOP;
 		dev_priv->pch_id = 0;
 	}

 	if (!pch)
 		drm_dbg_kms(&dev_priv->drm, "No PCH found.\n");

 	pci_dev_put(pch);
 }
	// SPDX-License-Identifier: MIT
	/*
	* Copyright 2019 Intel Corporation.
	*/

	#include "i915_drv.h"
	#include "intel_pch.h"

	/* Map PCH device id to PCH type, or PCH_NONE if unknown. */
	static enum intel_pch
	intel_pch_type(const struct drm_i915_private *dev_priv, unsigned short id)
	{
	switch (id) {
	case INTEL_PCH_IBX_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Ibex Peak PCH\n");
	drm_WARN_ON(&dev_priv->drm, !IS_GEN(dev_priv, 5));
	return PCH_IBX;
	case INTEL_PCH_CPT_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found CougarPoint PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_GEN(dev_priv, 6) && !IS_IVYBRIDGE(dev_priv));
	return PCH_CPT;
	case INTEL_PCH_PPT_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found PantherPoint PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_GEN(dev_priv, 6) && !IS_IVYBRIDGE(dev_priv));
	/* PantherPoint is CPT compatible */
	return PCH_CPT;
	case INTEL_PCH_LPT_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found LynxPoint PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
	drm_WARN_ON(&dev_priv->drm,
	IS_HSW_ULT(dev_priv) \|\| IS_BDW_ULT(dev_priv));
	return PCH_LPT;
	case INTEL_PCH_LPT_LP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found LynxPoint LP PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
	drm_WARN_ON(&dev_priv->drm,
	!IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
	return PCH_LPT;
	case INTEL_PCH_WPT_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found WildcatPoint PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
	drm_WARN_ON(&dev_priv->drm,
	IS_HSW_ULT(dev_priv) \|\| IS_BDW_ULT(dev_priv));
	/* WildcatPoint is LPT compatible */
	return PCH_LPT;
	case INTEL_PCH_WPT_LP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found WildcatPoint LP PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
	drm_WARN_ON(&dev_priv->drm,
	!IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
	/* WildcatPoint is LPT compatible */
	return PCH_LPT;
	case INTEL_PCH_SPT_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found SunrisePoint PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv));
	return PCH_SPT;
	case INTEL_PCH_SPT_LP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found SunrisePoint LP PCH\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_SKYLAKE(dev_priv) &&
	!IS_KABYLAKE(dev_priv) &&
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv));
	return PCH_SPT;
	case INTEL_PCH_KBP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Kaby Lake PCH (KBP)\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_SKYLAKE(dev_priv) &&
	!IS_KABYLAKE(dev_priv) &&
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv));
	/* KBP is SPT compatible */
	return PCH_SPT;
	case INTEL_PCH_CNP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Cannon Lake PCH (CNP)\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_CANNONLAKE(dev_priv) &&
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv));
	return PCH_CNP;
	case INTEL_PCH_CNP_LP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm,
	"Found Cannon Lake LP PCH (CNP-LP)\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_CANNONLAKE(dev_priv) &&
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv));
	return PCH_CNP;
	case INTEL_PCH_CMP_DEVICE_ID_TYPE:
	case INTEL_PCH_CMP2_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Comet Lake PCH (CMP)\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv) &&
	!IS_ROCKETLAKE(dev_priv));
	/* CometPoint is CNP Compatible */
	return PCH_CNP;
	case INTEL_PCH_CMP_V_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Comet Lake V PCH (CMP-V)\n");
	drm_WARN_ON(&dev_priv->drm,
	!IS_COFFEELAKE(dev_priv) &&
	!IS_COMETLAKE(dev_priv));
	/* Comet Lake V PCH is based on KBP, which is SPT compatible */
	return PCH_SPT;
	case INTEL_PCH_ICP_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Ice Lake PCH\n");
	drm_WARN_ON(&dev_priv->drm, !IS_ICELAKE(dev_priv));
	return PCH_ICP;
	case INTEL_PCH_MCC_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Mule Creek Canyon PCH\n");
	drm_WARN_ON(&dev_priv->drm, !IS_JSL_EHL(dev_priv));
	return PCH_MCC;
	case INTEL_PCH_TGP_DEVICE_ID_TYPE:
	case INTEL_PCH_TGP2_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Tiger Lake LP PCH\n");
	drm_WARN_ON(&dev_priv->drm, !IS_TIGERLAKE(dev_priv) &&
	!IS_ROCKETLAKE(dev_priv));
	return PCH_TGP;
	case INTEL_PCH_JSP_DEVICE_ID_TYPE:
	case INTEL_PCH_JSP2_DEVICE_ID_TYPE:
	drm_dbg_kms(&dev_priv->drm, "Found Jasper Lake PCH\n");
	drm_WARN_ON(&dev_priv->drm, !IS_JSL_EHL(dev_priv));
	return PCH_JSP;
	default:
	return PCH_NONE;
	}
	}

	static bool intel_is_virt_pch(unsigned short id,
	unsigned short svendor, unsigned short sdevice)
	{
	return (id == INTEL_PCH_P2X_DEVICE_ID_TYPE \|\|
	id == INTEL_PCH_P3X_DEVICE_ID_TYPE \|\|
	(id == INTEL_PCH_QEMU_DEVICE_ID_TYPE &&
	svendor == PCI_SUBVENDOR_ID_REDHAT_QUMRANET &&
	sdevice == PCI_SUBDEVICE_ID_QEMU));
	}

	static unsigned short
	intel_virt_detect_pch(const struct drm_i915_private *dev_priv)
	{
	unsigned short id = 0;

	/*
	* 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_TIGERLAKE(dev_priv) \|\| IS_ROCKETLAKE(dev_priv))
	id = INTEL_PCH_TGP_DEVICE_ID_TYPE;
	else if (IS_JSL_EHL(dev_priv))
	id = INTEL_PCH_MCC_DEVICE_ID_TYPE;
	else if (IS_ICELAKE(dev_priv))
	id = INTEL_PCH_ICP_DEVICE_ID_TYPE;
	else if (IS_CANNONLAKE(dev_priv) \|\|
	IS_COFFEELAKE(dev_priv) \|\|
	IS_COMETLAKE(dev_priv))
	id = INTEL_PCH_CNP_DEVICE_ID_TYPE;
	else if (IS_KABYLAKE(dev_priv) \|\| IS_SKYLAKE(dev_priv))
	id = INTEL_PCH_SPT_DEVICE_ID_TYPE;
	else if (IS_HSW_ULT(dev_priv) \|\| IS_BDW_ULT(dev_priv))
	id = INTEL_PCH_LPT_LP_DEVICE_ID_TYPE;
	else if (IS_HASWELL(dev_priv) \|\| IS_BROADWELL(dev_priv))
	id = INTEL_PCH_LPT_DEVICE_ID_TYPE;
	else if (IS_GEN(dev_priv, 6) \|\| IS_IVYBRIDGE(dev_priv))
	id = INTEL_PCH_CPT_DEVICE_ID_TYPE;
	else if (IS_GEN(dev_priv, 5))
	id = INTEL_PCH_IBX_DEVICE_ID_TYPE;

	if (id)
	drm_dbg_kms(&dev_priv->drm, "Assuming PCH ID %04x\n", id);
	else
	drm_dbg_kms(&dev_priv->drm, "Assuming no PCH\n");

	return id;
	}

	void intel_detect_pch(struct drm_i915_private *dev_priv)
	{
	struct pci_dev *pch = NULL;

	/* DG1 has south engine display on the same PCI device */
	if (IS_DG1(dev_priv)) {
	dev_priv->pch_type = PCH_DG1;
	return;
	}

	/*
	* The reason to probe ISA bridge instead of Dev31:Fun0 is to
	* make graphics device passthrough work easy for VMM, that only
	* need to expose ISA bridge to let driver know the real hardware
	* underneath. This is a requirement from virtualization team.
	*
	* In some virtualized environments (e.g. XEN), there is irrelevant
	* ISA bridge in the system. To work reliably, we should scan trhough
	* all the ISA bridge devices and check for the first match, instead
	* of only checking the first one.
	*/
	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
	unsigned short id;
	enum intel_pch pch_type;

	if (pch->vendor != PCI_VENDOR_ID_INTEL)
	continue;

	id = pch->device & INTEL_PCH_DEVICE_ID_MASK;

	pch_type = intel_pch_type(dev_priv, id);
	if (pch_type != PCH_NONE) {
	dev_priv->pch_type = pch_type;
	dev_priv->pch_id = id;
	break;
	} else if (intel_is_virt_pch(id, pch->subsystem_vendor,
	pch->subsystem_device)) {
	id = intel_virt_detect_pch(dev_priv);
	pch_type = intel_pch_type(dev_priv, id);

	/* Sanity check virtual PCH id */
	if (drm_WARN_ON(&dev_priv->drm,
	id && pch_type == PCH_NONE))
	id = 0;

	dev_priv->pch_type = pch_type;
	dev_priv->pch_id = id;
	break;
	}
	}

	/*
	* Use PCH_NOP (PCH but no South Display) for PCH platforms without
	* display.
	*/
	if (pch && !HAS_DISPLAY(dev_priv)) {
	drm_dbg_kms(&dev_priv->drm,
	"Display disabled, reverting to NOP PCH\n");
	dev_priv->pch_type = PCH_NOP;
	dev_priv->pch_id = 0;
	}

	if (!pch)
	drm_dbg_kms(&dev_priv->drm, "No PCH found.\n");

	pci_dev_put(pch);
	}