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authorArthur Heymans <arthur@aheymans.xyz>2016-05-19 16:06:09 +0200
committerMartin Roth <martinroth@google.com>2016-08-31 20:01:05 +0200
commit874a8f961ff537bc12cfca3d9937a07fcda2fe6e (patch)
treee9c9c1ba17c4ec15b5401a03350f06cf21a43c40 /src/mainboard/apple
parent868cd7128262ca8442301c2910ed843ab3f193ff (diff)
downloadcoreboot-874a8f961ff537bc12cfca3d9937a07fcda2fe6e.tar.xz
i945: Enable changing VRAM size
On i945 the vram size is the default 8mb. It is also possible to set it 1mb or 0mb hardcoding the GGC register in early_init.c The intel documentation on i945, "Mobile IntelĀ® 945 Express Chipset Family datasheet june 2008" only documents those three options. They are set using 3 bits. The documententation also makes mention of 4mb, 16mb, 32mb, 48mb, 64mb but not how to set it. The other non documented (straight forward) bit combinations allow to change the VRAM size to those other states. What this patch does is: - add those undocumented registers with their respective vram size to the i945 NB code; - make this a cmos option on targets that have this northbridge. TEST: build, flash to target, set cmos as desired and boot linux. On Debian it can be found using "dmesg | grep stolen". NOTE: dmesg message about reserved vram are quite different depending on linux version Change-Id: Ia71367ae3efb51bd64affd728407b8386e74594f Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/14819 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth <martinroth@google.com>
Diffstat (limited to 'src/mainboard/apple')
-rw-r--r--src/mainboard/apple/macbook21/cmos.default1
-rw-r--r--src/mainboard/apple/macbook21/cmos.layout11
2 files changed, 11 insertions, 1 deletions
diff --git a/src/mainboard/apple/macbook21/cmos.default b/src/mainboard/apple/macbook21/cmos.default
index 37018a443f..1cf350c4d2 100644
--- a/src/mainboard/apple/macbook21/cmos.default
+++ b/src/mainboard/apple/macbook21/cmos.default
@@ -17,3 +17,4 @@ fn_ctrl_swap=Disable
sticky_fn=Disable
power_management_beeps=Enable
low_battery_beep=Enable
+gfx_uma_size=8M \ No newline at end of file
diff --git a/src/mainboard/apple/macbook21/cmos.layout b/src/mainboard/apple/macbook21/cmos.layout
index 4b4b8de21b..8329347f52 100644
--- a/src/mainboard/apple/macbook21/cmos.layout
+++ b/src/mainboard/apple/macbook21/cmos.layout
@@ -59,7 +59,9 @@ entries
# coreboot config options: southbridge
408 1 e 1 nmi
#409 2 e 7 power_on_after_fail
-#411 5 r 0 unused
+
+# coreboot config options: northbridge
+411 3 e 11 gfx_uma_size
# coreboot config options: bootloader
416 512 s 0 boot_devices
@@ -124,6 +126,13 @@ enumerations
8 1 Yes
9 0 Secondary
9 1 Primary
+11 0 1M
+11 1 4M
+11 2 8M
+11 3 16M
+11 4 32M
+11 5 48M
+11 6 64M
# -----------------------------------------------------------------
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