On 7/29/2025 4:03 AM, Damien Le Moal wrote:
On 7/29/25 01:24, Borah, Chaitanya Kumar wrote:
On 7/28/2025 9:41 AM, Damien Le Moal wrote:
On 7/25/25 3:43 PM, Borah, Chaitanya Kumar wrote:
For some context in our kms_pm_rpm tests, we enable min_power policy for SATA
so that we can reach deep runtime power states and restore the original policy
after finishing. [5][6]
IIUC, the above change is based on spec and not something which can be
reverted. So as I see it, we have to drop this code path for external ports.
However I am not sure if we can achieve deep power states without enforcing it
through the sysfs entry.
Atleast for the basic-rte subtest, the test passes if we comment out the
functions controlling the SATA ports. We will need more testing to determine if
this approach work. Any thoughts on it?
Also, are there other ways to detect a port is external other than receiving
EOPNOTSUPP on the sysfs write?
The attached patch adds the "link_power_management_supported" sysfs device
attribute for drives connected to AHCI. Would that work for you ?
Yes this could work. I quickly hacked the test to ignore writing policy
if this file returns 0.
Here is the state of the machine I am testing on.
/sys/class/scsi_host/host0/link_power_management_supported: 0
/sys/class/scsi_host/host1/link_power_management_supported: 0
/sys/class/scsi_host/host2/link_power_management_supported: 0
/sys/class/scsi_host/host3/link_power_management_supported: 0
/sys/class/scsi_host/host4/link_power_management_supported: 1
/sys/class/scsi_host/host5/link_power_management_supported: 1
/sys/class/scsi_host/host6/link_power_management_supported: 1
/sys/class/scsi_host/host7/link_power_management_supported: 1
Looks good. My test machine looks exactly like this too.
I will send out this patch as it is useful anyway regardless of external/hotplug
ports since not all adapters/drives support LPM.
When posting this, can I tag it as a solution to the regression ?
Yes sure you can use it.
Adding Imre to the conversation if he has anything to say about this
change in our test.
Regards
Chaitanya
And in addition to this patch, I will work on a flexible way of ignoring
hotplug.
