mb/google/brya/var/vell: Disable PCH USB2 phy power gating
The patch disables PCH USB2 Phy power gating to prevent possible display
flicker issue for vell board. Please refer Intel doc#723158 for
more information.
BUG=b:293535284
TEST=build and boot vell
Change-Id: I8a4d633fbd362188aedef373e515c7bfe5c4327a
Signed-off-by: Shon Wang <shon.wang@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76770
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Derek Huang <derekhuang@google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
diff --git a/src/mainboard/google/brya/variants/vell/overridetree.cb b/src/mainboard/google/brya/variants/vell/overridetree.cb
index 5298a7e..c024796 100644
--- a/src/mainboard/google/brya/variants/vell/overridetree.cb
+++ b/src/mainboard/google/brya/variants/vell/overridetree.cb
@@ -71,6 +71,10 @@
register "tcss_ports[3]" = "TCSS_PORT_DEFAULT(OC3)"
register "sagv" = "SaGv_Enabled"
+ # As per Intel Advisory doc#723158, the change is required to prevent possible
+ # display flickering issue.
+ register "usb2_phy_sus_pg_disable" = "1"
+
# Set EPP to 50%: 50 * 256 / 100 = 0x80
register "enable_energy_perf_pref" = "true"
register "energy_perf_pref_value" = "0x80"