I was trying to run platform_InstallTestImage on a squawks DUT with Servo V3. The test is basically powering off the DUT, switches the USB key to servo, downloads the image to usb key, starts the DUT in recovery mode, switches the USB key to DUT thus booting from the USB and installing Chrome OS. Because I'm working on porting iSCSI to Servo v3 ( http://crbug.com/570766 ) for this test, instead of downloading the image, I was setting up an iSCSI connection and exposing the Servo as an USB stick to DUT, other than that the sequence of operations is the same.

I noticed that sometimes the DUT was not starting in recovery mode, but instead in normal mode, and sometimes it did not start at all when setting power_state:rec. I thought it may be because I'm upgrading the BB kernel to 4.4, but after some tests I could reproduce the behavior on the current 3.8.13 kernel (although less frequently).

However today I was also testing with a samus DUT and I could reproduce the behavior with both 4.4 and 3.8 kernels. After the suggestion from @shawnn, I tried to run `dut-control power_state:rec` multiple times in a row, to see if the problem still happens. I was testing with a beaglebone_servo-release/R52-8296.0.0/test image for BB (with old 3.8 kernel) and the problem happened. Also running a simplified version of the test which only starts the DUT in recovery mode and boots from USB also confirmed this behavior for samus.

I attached the servod.log (servod started with BOARD=samus, DEBUG=1) for the 4 consecutive `dut-control power_state:rec`. The first 2 times, I did boot in normal mode (instead of recovery), 3rd time the DUT booted in recovery mode, and the 4th time the DUT also booted in normal mode (instead of recovery).
 

Deleted: servod8_3.8_samus_dut-control_repeatedly_no_removable.log 829 KB

servod8_3.8_samus_dut-control_repeatedly_no_removable.log 829 KB View Download