the following patch was just integrated into master: commit 3ac446036988bca020d902bd9b5c580cd367d9bb Author: Aaron Durbin adurbin@chromium.org Date: Wed Oct 16 09:21:55 2013 -0700
rambi: disable internal pullups on ram_id[2:0]
The ram_id[2:0] signals have stuffing options for pull up/down with values of 10K. However, the default pulldown values for these pads are 20K. Therefore, one can't read a high value because of the high voltage threshold is 0.65 * Vref. Therefore the high signals are marginal at best.
Fix this issue by disabling the internal pull for the pads connected to ram_id[2:0].
BUG=chrome-os-partner:23350 BRANCH=None TEST=Built and checked that ram_id[2:0] is properly read now.
Change-Id: Ib414d5798b472574337d1b71b87a4cf92f40c762 Signed-off-by: Aaron Durbin adurbin@chromium.org Reviewed-on: https://chromium-review.googlesource.com/173211 Reviewed-by: Shawn Nematbakhsh shawnn@chromium.org Reviewed-by: Bernie Thompson bhthompson@chromium.org
See http://review.coreboot.org/4885 for details.
-gerrit