Files
lbmk/config/coreboot/default/patches/0015-nb-haswell-lock-policy-regs-when-disabling-IOMMU.patch
T
Leah Rowe 2edd583aee Add ThinkPad X270 coreboot port from Kat Inskip
Courtesy of Kat Inskip who ported this board.

Headphone output doesn't work at the moment, due to incorrect verb.
Intel VBT is also wrong. Both are taken from another board.

This will be amended later with the correct verb and VBT.

Signed-off-by: Leah Rowe <leah@libreboot.org>
2026-02-21 08:26:44 +00:00

56 lines
2.0 KiB
Diff

From 18216387e5c40ec3c80c63ec25e9b0c55a009cff Mon Sep 17 00:00:00 2001
From: Leah Rowe <info@minifree.org>
Date: Sat, 4 May 2024 02:00:53 +0100
Subject: [PATCH 15/48] nb/haswell: lock policy regs when disabling IOMMU
Angel Pons told me I should do it. See comments here:
https://review.coreboot.org/c/coreboot/+/81016
I see no harm in complying with the request. I'll merge
this into the main patch at a later date and try to
get this upstreamed.
Just a reminder: on Optiplex 9020 variants, Xorg locks up
under Linux when tested with a graphics card; disabling
IOMMU works around the issue. Intel graphics work just fine
with IOMMU turned on. Libreboot disables IOMMU by default,
on the 9020, so that users can install graphics cards easily.
Signed-off-by: Leah Rowe <info@minifree.org>
---
src/northbridge/intel/haswell/early_init.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/src/northbridge/intel/haswell/early_init.c b/src/northbridge/intel/haswell/early_init.c
index 1a7e0b1076..e9506ee830 100644
--- a/src/northbridge/intel/haswell/early_init.c
+++ b/src/northbridge/intel/haswell/early_init.c
@@ -160,17 +160,16 @@ static void haswell_setup_iommu(void)
const u32 capid0_a = pci_read_config32(HOST_BRIDGE, CAPID0_A);
u8 enable_iommu = get_uint_option("iommu", 1);
- if (!enable_iommu)
- return;
-
if (capid0_a & VTD_DISABLE)
return;
- /* Setup BARs: zeroize top 32 bits; set enable bit */
- mchbar_write32(GFXVTBAR + 4, GFXVT_BASE_ADDRESS >> 32);
- mchbar_write32(GFXVTBAR + 0, GFXVT_BASE_ADDRESS | 1);
- mchbar_write32(VTVC0BAR + 4, VTVC0_BASE_ADDRESS >> 32);
- mchbar_write32(VTVC0BAR + 0, VTVC0_BASE_ADDRESS | 1);
+ if (enable_iommu) {
+ /* Setup BARs: zeroize top 32 bits; set enable bit */
+ mchbar_write32(GFXVTBAR + 4, GFXVT_BASE_ADDRESS >> 32);
+ mchbar_write32(GFXVTBAR + 0, GFXVT_BASE_ADDRESS | 1);
+ mchbar_write32(VTVC0BAR + 4, VTVC0_BASE_ADDRESS >> 32);
+ mchbar_write32(VTVC0BAR + 0, VTVC0_BASE_ADDRESS | 1);
+ }
/* Set L3HIT2PEND_DIS, lock GFXVTBAR policy config registers */
u32 reg32;
--
2.47.3