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authorBill Richardson <wfrichar@chromium.org>2014-11-05 12:43:57 -0800
committerchrome-internal-fetch <chrome-internal-fetch@google.com>2014-11-06 02:28:22 +0000
commit41cde665166da1aced2ece17f7b503c78cdb5c8f (patch)
tree6e95a130dadbd38846ad8cf32124ccdbb49ff353 /include
parentf0809a23997d66265e625d23ebef8dba1465732f (diff)
downloadchrome-ec-41cde665166da1aced2ece17f7b503c78cdb5c8f.tar.gz
Samus: Handle fan startup in the EC, not the fan controller
The fans on samus have a recommended minimum duty cycle of 20% while running, but 30% in order to start. We've been using the EC's built-in fan controller for the start requirement, but it has a minimum fast-start duty cycle of 50%. It turns out that that speed is noticeably noisy. This change handles the startup with logic in the EC instead, so that the fan only tries to spin at 30% initially (or if it drops too much below the minimum turning speed). BUG=chrome-os-partner:33429 BRANCH=ToT,samus TEST=make buildall -j Boot the system, let it idle with the browser windows closed, the browse a bit, then idle. Listen for changes to the fans. Before, I could hear the fans kick in and out as the AP load changed. Now it's much quieter. Change-Id: Id35215520c064eb6843686ec8bb5f3618dac6cf6 Signed-off-by: Bill Richardson <wfrichar@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/227658 Reviewed-by: Randall Spangler <rspangler@chromium.org>
Diffstat (limited to 'include')
-rw-r--r--include/fan.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/fan.h b/include/fan.h
index a8352987d8..bd94ba8bd1 100644
--- a/include/fan.h
+++ b/include/fan.h
@@ -11,7 +11,9 @@
/* Characteristic of each physical fan */
struct fan_t {
unsigned int flags;
+ /* rpm_min is to keep turning. rpm_start is to begin turning */
int rpm_min;
+ int rpm_start;
int rpm_max;
/* Hardware channel number (the meaning is chip-specific) */
int ch;