Hi all, Dne 9.12.2017 v 20:40 Rudolf Marek napsal(a): > Turn on VGA_16BIT_EN if supported by the bridge It turns out, there are at least two bridges, where this bit is broken: PEX 8114BC PCI Express-to-PCI/PCI-X Bridge Errata Documentation PEX 8114BA PCI Express-to-PCI/PCI-X Bridge Errata Documentation Description In PCI or PCI-X Forward or Reverse Transparent Bridge mode, the Bridge Control register VGA 16-Bit Decode bit (offset 3Ch[20]) does not function correctly. PCI Address bits [9:0] are correctly decoded; however, PCI Address bits [15:10] are not decoded, causing the PEX 8114 to ignore these Address lines. It seems that this feature is required by windoze server edition: "Virtual bridges that comply with PCI Express also comply with PCI-to-PCI Bridge Architecture Specification, Revision 1.1. In addition, VGA 16-bit decode (Section 3.2.5.18, "Bridge Control Register, bit 4") and SSID and SSVID (Section 3.2.5.13) from PCI-to-PCI Bridge Architecture Specification, Revision 1.2, must also be supported." I tried to have a look, how to implement the resources to deal with the ISA aliasing, but I definitely need some pointers how to do that. Overall approach: For all PCI bridges, try to enable the 16-bit I/O (older bridges have this bit RO), minus the two broken above, note the state in say, dev->hasvga16, perhaps do this in pci/quirks.c ? During the PCI bridge enumeration, add extra resources if dev->hasvga16 is zero. I hope that the resource allocator can fix it on its own. We should do that regardless of state of PCI_BRIDGE_CTL_VGA as pci_set_vga_state() could switch it later. I don't know if it would be enough to modify pci_read_bridge_bases() in drivers/pci/probe.c and add there all the ISA aliases of 0x3b0-0x3df (similarly it adds transparent bridge resources) There is 48 resources to be added, I hope there is no limit, seems there is just linked list. N= 0 - F 0xN3b0-0xN3df 0xN7b0-0xN7df 0xNfb0-0xNfdf Thanks Rudolf
