82d5123e1c
On VCCin there was an oscillation which occurred just as the kernel started (kernel starting... message). On some devices, this behavior seems even worse. In previous platforms VCCin toggled for a few ms and then was stable. For volteer, this happens at the same point in time for around 40ms. However, it starts oscillating again later in the boot sequence. Once at the root shell, it seems to oscillate indefinitely at around 100-200Hz (very variable though). To fix this we need to control the deep C-state voltage slew rate.We have options for controlling the deep C-state voltage slew rate through FSP UPDs. This patch expose the following FSP UPD interface into coreboot: - AcousticNoiseMitigation - FastPkgCRampDisable - SlowSlewRate We are setting SlowSlewRate for all volteer boards to 2 which is Fast/8. TGL has a single VR domain(Vccin). Hence, the chip config is updated to allow mainboards to set a single value instead of an array and FSP UPDs are accordingly set. BUG=b:153015585 BRANCH=firmware-volteer-13672.B TEST= Measure the change in noise level by changing the UPD values. Signed-off-by: Shaunak Saha <shaunak.saha@intel.com> Change-Id: Ica7f1f29995df33bdebb1fd55169cdb36f329ff8 Reviewed-on: https://review.coreboot.org/c/coreboot/+/50870 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Furquan Shaikh <furquan@google.com> |
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| .. | ||
| spd | ||
| variants | ||
| board_info.txt | ||
| bootblock.c | ||
| chromeos.c | ||
| chromeos.fmd | ||
| dsdt.asl | ||
| ec.c | ||
| fw_config.c | ||
| Kconfig | ||
| Kconfig.name | ||
| mainboard.asl | ||
| mainboard.c | ||
| Makefile.inc | ||
| romstage.c | ||
| smihandler.c | ||