ata: libata_eh: Add debug messages to ata_eh_link_set_lpm()

To facilitate field debugging of link power management related issues,
add a debug message to ata_eh_link_set_lpm() to easily track LPM policy
changes done from EH context, that is, during device scan and
revalidation, error handling, and when a policy change is issued through
a host sysfs link_power_management_policy attribute.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20250701125321.69496-11-dlemoal@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 7f5d13f9ca73fa095af7359821e0a9b947916ba8..0f9c30f9bc1ee565ee4f95914f9ddb15a272a5a1 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2140,6 +2140,8 @@ static int ata_eh_link_set_lpm(struct ata_link *link,
        if (WARN_ON_ONCE(policy == ATA_LPM_UNKNOWN))
                return 0;
 
+       ata_link_dbg(link, "Set LPM policy: %d -> %d\n", old_policy, policy);
+
        /*
         * DIPM is enabled only for ATA_LPM_MIN_POWER,
         * ATA_LPM_MIN_POWER_WITH_PARTIAL, and ATA_LPM_MED_POWER_WITH_DIPM, as