broadwell mrc has better peg handling and can support 16gb
modules on broadwell machines - the blob can be used on haswell
machines too, instead of haswell mrc, and it might support 16gb
modules on these machines (not yet tested, but using broadwell
mrc does at least boot as reliably as haswell mrc anyway)
one little quirk with haswell mrc is that it actually handles
vga decode, disabling the igpu entirely, when a dgpu is used.
the broadwell mrc enables both GPUs and does not handle vga
decoding, so we must handle this the usual way; my patch for
this was merged upstream and i'm also adding it to libreboot,
which currently uses an older coreboot revision. this is needed
for dgpu to work. see patch:
0040-nb-haswell-Disable-iGPU-when-dGPU-is-used.patch
broadwell mrc may also make dealing with nvidia optimus setups
more reliable, on laptops that have nvidia GPUs, but this patch
does not add bmrc configs for t440p/w541
NOTE: on t440p/w541 laptops with nvidia graphics, the video output
is wired to intel but rendering can be offloaded to nvidia. in this
setup, we want vga decode to be done on intel, so i've set these
configs to enable CONFIG_ONBOARD_VGA_IS_PRIMARY (set it to y)
Signed-off-by: Leah Rowe <leah@libreboot.org>
Leah Rowe