diff --git a/src/coreboot/default.nix b/src/coreboot/default.nix index 904cf90..5c3b226 100644 --- a/src/coreboot/default.nix +++ b/src/coreboot/default.nix @@ -107,6 +107,8 @@ stdenv.mkDerivation { ./patches/0002-kgpe-d16-do-not-enable-hw-monitor-until-kernel-boots.patch ./patches/0026-kgpe-d16-start-w83667hg-a-watchdog-during-romstage.patch ./patches/0004-kgpe-d16-romstage.c-do-a-double-reset-on-other_reset.patch + # does not seem necessary; kept in-tree but unapplied for future use + #./patches/0003-southbridge-amd-sb700-disable-two-hacks.patch # am1i patches ./patches/0021-am1i-omit-amdfw.rom-completely-it-has-broken-address.patch diff --git a/src/coreboot/patches/0003-southbridge-amd-sb700-disable-two-hacks.patch b/src/coreboot/patches/0003-southbridge-amd-sb700-disable-two-hacks.patch new file mode 100644 index 0000000..6d92781 --- /dev/null +++ b/src/coreboot/patches/0003-southbridge-amd-sb700-disable-two-hacks.patch @@ -0,0 +1,44 @@ +From aa5b636937bd1ce6dd9ec414ddca293f19085e31 Mon Sep 17 00:00:00 2001 +From: Your Name +Date: Tue, 13 Jun 2023 01:16:05 -0700 +Subject: [PATCH 3/4] southbridge/amd/sb700: disable two hacks + +This commit disables two hacks: + + - "RPR 2.26 Alter CPU reset timing", introduced by commit + d1b6ff80c017e671c1e2229ee0d659e491ab53f5 + + - "Work around system clock drift issues", introduced by commit + 905507c3790829e8a6352d857bbad446e6c1c4e6 + +Neither of the commits which introduced these two hacks contains any +useful information in the commit message, nor am I able to find +anything about altering CPU reset timing in section 2.26 of the +SB700 "Register Programming Requirements" (RPR) document. +--- + src/southbridge/amd/sb700/early_setup.c | 2 ++ + 1 file changed, 2 insertions(+) + +diff --git a/src/southbridge/amd/sb700/early_setup.c b/src/southbridge/amd/sb700/early_setup.c +index 4dfe6dd2ee2..21c1353c3d3 100644 +--- a/src/southbridge/amd/sb700/early_setup.c ++++ b/src/southbridge/amd/sb700/early_setup.c +@@ -686,6 +686,7 @@ static void sb700_pmio_por_init(void) + byte |= 0xc0; + pmio_write(0xbb, byte); + ++#if 0 + #if IS_ENABLED(CONFIG_SOUTHBRIDGE_AMD_SUBTYPE_SP5100) + /* RPR 2.26 Alter CPU reset timing */ + byte = pmio_read(0xb2); +@@ -698,6 +699,7 @@ static void sb700_pmio_por_init(void) + byte |= 0x1 << 7; /* Disable 25MHz oscillator buffer */ + pmio_write(0xd4, byte); + #endif ++#endif + } + + /* +-- +2.39.1 +