From e15e64054c059f58569b4aa9ce132aee8c8a2e48 Mon Sep 17 00:00:00 2001 From: Ren Kuo Date: Wed, 22 Dec 2021 18:42:43 +0800 Subject: [PATCH] mb/google/dedede/var/magolor: Set core display clock to 172.8 MHz When using the default initial core display clock frequency, Magolor has a rare stability issue where the startup of Chrome OS in secure mode may hang. Slowing the initial core display clock frequency down to 172.8 MHz as per Intel recommendation avoids this problem. Depend on CL: https://review.coreboot.org/c/coreboot/+/60009 The CdClock=0xff is set in dedede baseboard,and we overwrite it as 0x0 (172.8 MHz) for magolor. BUG=b:206557434 BRANCH=dedede TEST=Build firmware and verify on fail DUTs. Check the DUTs can boot up in secure mode well. Change-Id: I5a0ad2bed79b37775184f0bd0a0ef024900cbe34 Signed-off-by: Ren Kuo Reviewed-on: https://review.coreboot.org/c/coreboot/+/60301 Tested-by: build bot (Jenkins) Reviewed-by: Nico Huber Reviewed-by: Angel Pons --- src/mainboard/google/dedede/variants/magolor/overridetree.cb | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/mainboard/google/dedede/variants/magolor/overridetree.cb b/src/mainboard/google/dedede/variants/magolor/overridetree.cb index 66fc4ea02f..e0af22dd49 100644 --- a/src/mainboard/google/dedede/variants/magolor/overridetree.cb +++ b/src/mainboard/google/dedede/variants/magolor/overridetree.cb @@ -108,6 +108,9 @@ chip soc/intel/jasperlake register "SlowSlewRate" = "SlewRateFastBy8" register "FastPkgCRampDisable" = "1" + # Core Display Clock Frequency selection + register "cd_clock" = "CD_CLOCK_172_8_MHZ" + device domain 0 on device pci 04.0 on chip drivers/intel/dptf