File 0001-Fix-PCIe-LER-when-GRUB2-accesses-non-enabl... of Package grub2

Overview Repositories Revisions Requests Users Attributes Meta

File 0001-Fix-PCIe-LER-when-GRUB2-accesses-non-enabled-MMIO-da.patch of Package grub2 (Revision fdf485e95bb873fb146c132935b09d74)

Currently displaying revision fdf485e95bb873fb146c132935b09d74 , Show latest

From 2f06e09673e48f6a91486a8ad38f45c160d537fe Mon Sep 17 00:00:00 2001
From: "mike.travis@hpe.com" <mike.travis@hpe.com>
Date: Wed, 28 Mar 2018 11:42:18 -0500
Subject: 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 <mike.travis@hpe.com>
---
 grub-core/video/efi_uga.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/grub-core/video/efi_uga.c b/grub-core/video/efi_uga.c
index 464ede874..32ef7efbc 100644
--- a/grub-core/video/efi_uga.c
+++ b/grub-core/video/efi_uga.c
@@ -95,9 +95,18 @@ 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 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;
 
-- 
2.13.6

Places

File 0001-Fix-PCIe-LER-when-GRUB2-accesses-non-enabled-MMIO-da.patch of Package grub2 (Revision fdf485e95bb873fb146c132935b09d74)

Places