From a897321d9c318c18c92c6431115fd9be71fedba1 Mon Sep 17 00:00:00 2001 From: "mike.travis@hpe.com" Date: Wed, 28 Mar 2018 11:42:18 -0500 Subject: [PATCH 288/288] efi/uga: Fix PCIe LER when GRUB2 accesses non-enabled MMIO data from VGA A GPU inserted into a PCIe I/O slot disappears during system startup. The problem centers around GRUB and a specific VGA init function in efi_uga.c. This causes an LER (Link Error Recorvery) because the MMIO memory has not been enabled before attempting access. The fix is to add the same coding used in other VGA drivers, specifically to add a check to insure that it is indeed a VGA controller. And then enable the MMIO address space with the specific bits. Signed-off-by: Mike Travis Reviewed-by: Daniel Kiper --- grub-core/video/efi_uga.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/grub-core/video/efi_uga.c b/grub-core/video/efi_uga.c index 1d4091c5631..97a607c01a5 100644 --- a/grub-core/video/efi_uga.c +++ b/grub-core/video/efi_uga.c @@ -94,10 +94,19 @@ static int find_card (grub_pci_device_t dev, grub_pci_id_t pciid, void *data) { struct find_framebuf_ctx *ctx = data; - grub_pci_address_t addr; + grub_pci_address_t addr, rcaddr; + grub_uint32_t subclass; addr = grub_pci_make_address (dev, GRUB_PCI_REG_CLASS); - if (grub_pci_read (addr) >> 24 == 0x3) + subclass = (grub_pci_read (addr) >> 16) & 0xffff; + + if (subclass != GRUB_PCI_CLASS_SUBCLASS_VGA) + return 0; + + /* Enable MEM address spaces */ + rcaddr = grub_pci_make_address (dev, GRUB_PCI_REG_COMMAND); + grub_pci_write_word (rcaddr, grub_pci_read_word (rcaddr) | GRUB_PCI_COMMAND_MEM_ENABLED); + { int i; -- 2.17.1