Attention is currently required from: Bora Guvendik, Cliff Huang, Selma Bensaid. Tim Wawrzynczak has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/61783 )
Change subject: mb/google/brya: remove the delay from for WWAN _ON method. ......................................................................
Patch Set 2:
(3 comments)
Commit Message:
https://review.coreboot.org/c/coreboot/+/61783/comment/f5e55233_ff8ba6f2 PS1, Line 9: During booting to OS, ACPI calls _ON and immediately calls _OFF method.
I think you are correct!
Ack
https://review.coreboot.org/c/coreboot/+/61783/comment/85e862ce_84409bde PS1, Line 16: INFO kernel: [ 0.189801] ACPI: Power Resource [RTD3] (on) : INFO kernel: [ 0.206510] ACPI: Power Resource [RTD3] (off)
I think you are correct. Thanks for pointing out. […]
Yep sure does! _ON has that 1s delay in there.
File src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/61783/comment/72fc65cb_553f8ba9 PS1, Line 158: register "reset_delay_ms" = "10"
The datasheet only shows there is 20 seconds HW initialization after de-assertion of PERST#. […]
With un-characterized ramp-up and ramp-down times on these signals, a 10ms delay is probably pretty safe and also not excessive. WDYT?