include/hw/pci/pci_ids.h
A very last minute realisation is that this is not needed. Its purpose is to make sure anything else that references LPC device ID is given the hacked-in host's ID. but in verifying the patch validity it appears this not referenced anywhere, other than where its taken care on in ich9_lpc.c
for completeness, here it is:
patch
---------------------
diff --git a/include/hw/pci/pci_ids.h b/include/hw/pci/pci_ids.h
index e597070..b76c61b 100644
--- a/include/hw/pci/pci_ids.h
+++ b/include/hw/pci/pci_ids.h
@@ -130,7 +130,19 @@
#define PCI_DEVICE_ID_INTEL_ICH9_5 0x2919
#define PCI_DEVICE_ID_INTEL_ICH9_6 0x2930
#define PCI_DEVICE_ID_INTEL_ICH9_7 0x2916
-#define PCI_DEVICE_ID_INTEL_ICH9_8 0x2918
+
+/* TODO: Replace this hack for a non-hack!
+ * PCI_DEVICE_ID_INTEL_ICH9_8 must be set to
+ * `setpci -s 00:1f.0 0x02.w` (LPC device id)
+ * of the host - so that guest LPC represents
+ * the archiecture of device 2 (IGD). This is
+ * important to i915 kernel module */
+#define BEARLAKE 0x2918 // QEMU DEFAULT
+#define COUGARPOINT 0x1c4e
+#define PANTHERPOINT 0x
+#define LYNXPOINT 0x8c4e
+
+#define PCI_DEVICE_ID_INTEL_ICH9_8 COUGARPOINT
#define PCI_DEVICE_ID_INTEL_82801I_UHCI1 0x2934
#define PCI_DEVICE_ID_INTEL_82801I_UHCI2 0x2935