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-rw-r--r--config/coreboot/default/patches/0040-nb-haswell-Disable-iGPU-when-dGPU-is-used.patch54
1 files changed, 54 insertions, 0 deletions
diff --git a/config/coreboot/default/patches/0040-nb-haswell-Disable-iGPU-when-dGPU-is-used.patch b/config/coreboot/default/patches/0040-nb-haswell-Disable-iGPU-when-dGPU-is-used.patch
new file mode 100644
index 00000000..7a02d902
--- /dev/null
+++ b/config/coreboot/default/patches/0040-nb-haswell-Disable-iGPU-when-dGPU-is-used.patch
@@ -0,0 +1,54 @@
+From c6ce9c635e6576c86c546177c3d770dec2f3c9ae Mon Sep 17 00:00:00 2001
+From: Leah Rowe <info@minifree.org>
+Date: Fri, 23 Feb 2024 13:33:31 +0000
+Subject: [PATCH 1/1] nb/haswell: Disable iGPU when dGPU is used
+
+This is usually is handled by Haswell mrc.bin, disabling VGA
+decode on the iGPU when a dGPU is installed. However, Broadwell
+mrc.bin does not, so the iGPU and dGPU are both enabled.
+
+This patch disables legacy VGA cycles for iGPU, under such
+conditions. It has been tested on Broadwell mrc.bin when
+using a graphics card on Dell OptiPlex 9020 SFF (currently
+under review at this time of writing, submitted by Mate
+Kukri).
+
+This patch has also been tested when Haswell mrc.bin is used,
+and there are seemingly no breaking changes caused by it.
+
+Change-Id: I1df0a3aa42f8475b7741007bf3e28c2e089d916b
+Signed-off-by: Leah Rowe <info@minifree.org>
+Reviewed-on: https://review.coreboot.org/c/coreboot/+/80717
+Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
+Reviewed-by: Nico Huber <nico.h@gmx.de>
+---
+ src/northbridge/intel/haswell/gma.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/src/northbridge/intel/haswell/gma.c b/src/northbridge/intel/haswell/gma.c
+index 6e6948b70f..48a0ba54c7 100644
+--- a/src/northbridge/intel/haswell/gma.c
++++ b/src/northbridge/intel/haswell/gma.c
+@@ -461,12 +461,19 @@ static void gma_generate_ssdt(const struct device *dev)
+ drivers_intel_gma_displays_ssdt_generate(&chip->gfx);
+ }
+
++static void gma_func0_disable(struct device *dev)
++{
++ /* Disable VGA decode */
++ pci_or_config16(pcidev_on_root(0, 0), GGC, 1 << 1);
++}
++
+ static struct device_operations gma_func0_ops = {
+ .read_resources = pci_dev_read_resources,
+ .set_resources = pci_dev_set_resources,
+ .enable_resources = pci_dev_enable_resources,
+ .init = gma_func0_init,
+ .acpi_fill_ssdt = gma_generate_ssdt,
++ .vga_disable = gma_func0_disable,
+ .ops_pci = &pci_dev_ops_pci,
+ };
+
+--
+2.39.2
+