I am seeing a large number of BBBs with M627 eMMC that are failing. They either outright fail to operate under u-boot, or have I/O failures either during boot or a few seconds/minutes after boot.
These BBBs have rootfs on the eMMC and they ran the affected v6.1.38 version for some time. We had a number of dead MK27 chips, pretty much matching the issues covered in this topic, but the M627 chips held up a couple of months ago.
I’m posting here in hope of understanding what effect the problematic aggressive PM patch might have in the M627 in long-term operation. The rootfs is running from the eMMC and the BBBs have been updated, to the best of my knowledge, to a kernel with 3edf588e7fe00e90d1dc7fb9e599861b2c2cf442 reverted.
Is there a possibility of the M627 slowly dying over time, after exposure to the faulty kernel?
I moved this to a new thread… the split the MK27 (now solved) with the M627 issues you see.. I personally haven’t looked at long term running tests of the M627 as i had been deep in the MK27..
Our customer is seeing considerable exposure to failing M627 chips after a couple of months and we’ll put some M627 BBBs in long-term runs with the affected kernel to get a better understand of what the impact may be on these units.
I’ll keep you posted on what we find, if we eventually do.
We were fortunate to have logs and database records that allowed to rebuild the wear history of these affected devices.
Based on the data that we collected our conclusion for the M62704 is
EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B increases two steps (20%) at each 12 (that’s right, twelve) days of uptime on average;
EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A increases about 10% within the same time period;
The eMMCs still appear to retain data and we can access their filesystems if we mount them readonly and without journal. Occasionally we get I/O errors or an unresponsive chip.
Most of the affected eMMCs in the boards that we collected freak out at some point if we try any kind of write operation on them (which is expected, given their wear level).
The above is, of course, contingent on the workload of the software running on the BBB, but the speed up in wear is evident from the moment that we install an affected kernel.
I hope this helps, regarding assessing the impact of this patch on the M627. Stay safe!