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| author | Randall Spangler <rspangler@chromium.org> | 2014-03-06 14:26:42 -0800 |
|---|---|---|
| committer | chrome-internal-fetch <chrome-internal-fetch@google.com> | 2014-03-07 02:21:03 +0000 |
| commit | 9de183a5d66aa7c07287f6b7793f6e266b6b376b (patch) | |
| tree | 0990ddc573b8471848aa4edb9be67ed594594614 | |
| parent | fcdb93668a32f3d2d311f113484eed1df5c613de (diff) | |
| download | chrome-ec-9de183a5d66aa7c07287f6b7793f6e266b6b376b.tar.gz | |
rambi: Add 7 ms delay before turning off PP3300_DX at shutdown
This works around an issue where LCDVCC falls too slowly. The impact
is to slow shutdown by 7 ms, which isn't noticeable to the user.
BUG=chrome-os-partner:26561
BRANCH=rambi
TEST=shut down rambi; still shuts down, and ~7 ms more time is spent
in S0->S3 state.
before:
[429.933010 power state 3 = S0, in 0x043f]
[429.933240 power state 7 = S0->S3, in 0x043f]
[429.933614 power state 2 = S3, in 0x042b]
[429.934013 power state 8 = S3->S5, in 0x0428]
after:
[20.355975 power state 3 = S0, in 0x003f]
[20.356194 power state 7 = S0->S3, in 0x003f]
[20.363957 power state 2 = S3, in 0x002c]
[20.364179 power state 8 = S3->S5, in 0x002c]
[20.364877 power state 1 = S5, in 0x0008]
Change-Id: Ie843bdcf740f3dbc1b866a0356cea2a8b42d4194
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/189092
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
| -rw-r--r-- | power/baytrail.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/power/baytrail.c b/power/baytrail.c index b44e1b8e27..5349045520 100644 --- a/power/baytrail.c +++ b/power/baytrail.c @@ -314,6 +314,7 @@ enum power_state power_handle_state(enum power_state state) gpio_set_level(GPIO_CPU_PROCHOT, 0); /* Turn off power rails */ + msleep(7); /* Small delay; see crosbug.com/p/26561 */ gpio_set_level(GPIO_PP3300_DX_EN, 0); #ifdef CONFIG_USB_PORT_POWER_IN_S3 |