I would prefer that we use a consistent decision to enable it
across all stages of coreboot. If a specific card always needs
power, the user shouldn't turn it off. What would be left to
do is to move the current enabling/disabling from ramstage to
romstage. e.g.
void h8_early_init(void)
{
/* comment why we might need it early */
h8_wwan_enable(h8_has_wwan(dev) && h8_wwan_nv_enable());
}
2 comments:
Patch Set #7, Line 10: support SMBus, is installed it pulls the lines low.
Looks like such a card would not be spec compliant:
"Care should be taken in the design of both the input and output stages
of SMBus devices, in order not to load the bus when their power plane
is turned off, i.e. powered-down devices must provide no leakage path
to ground."
Probably worth to mention here.
File src/mainboard/lenovo/t420/early_init.c:
Patch Set #7, Line 82: * ramstage will turn it off, in case it's not needed.
How to tell if it's not needed? There may be more going on on the
SMBus than just reading SPDs.
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