From 6a9c4b35e6696a63805b6da5e4889c6986e9ee1b Mon Sep 17 00:00:00 2001 From: Rui Guo Date: Wed, 19 Jun 2013 21:10:23 +0800 Subject: [PATCH] drm/i915: Fix PCH detect with multiple ISA bridges in VM 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. Signed-off-by: Rui Guo [danvet: Fixup conflict with the num_pch_pll removal. And add subsystem header to the commit message headline.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index deaa32e8113bfa..062cbda1bf4a6c 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -465,9 +465,15 @@ void intel_detect_pch(struct drm_device *dev) * 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. */ pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL); - if (pch) { + while (pch) { + struct pci_dev *curr = pch; if (pch->vendor == PCI_VENDOR_ID_INTEL) { unsigned short id; id = pch->device & INTEL_PCH_DEVICE_ID_MASK; @@ -496,10 +502,18 @@ void intel_detect_pch(struct drm_device *dev) DRM_DEBUG_KMS("Found LynxPoint LP PCH\n"); WARN_ON(!IS_HASWELL(dev)); WARN_ON(!IS_ULT(dev)); + } else { + goto check_next; } + pci_dev_put(pch); + break; } - pci_dev_put(pch); +check_next: + pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, curr); + pci_dev_put(curr); } + if (!pch) + DRM_DEBUG_KMS("No PCH found?\n"); } bool i915_semaphore_is_enabled(struct drm_device *dev)