Commit fa997b0576c9 ("ata: ahci: Do not enable LPM if no LPM states are
supported by the HBA") introduced an early return in
ahci_update_initial_lpm_policy() to ensure that the target_lpm_policy
of ports belonging to a host that does not support the Partial, Slumber
and DevSleep power states is unchanged and remains set to
ATA_LPM_UNKNOWN and thus prevents the execution of
ata_eh_link_set_lpm().
However, a user or a system daemon (e.g. systemd-udevd) may still
attempt changing the LPM policy through the sysfs
link_power_management_policy of the host.
Improve this to prevent sysfs LPM policy changes by setting the flag
ATA_FLOAG_NO_LPM for the port of such host, and initialize the port
target_lpm_policy to ATA_LPM_MAX_POWER to guarantee that no unsupported
low power state is being used on the port and its link.
Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
drivers/ata/ahci.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 34698ae39f55..737f5d1bde11 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1793,7 +1793,10 @@ static void ahci_update_initial_lpm_policy(struct ata_port *ap)
if ((ap->host->flags & ATA_HOST_NO_PART) &&
(ap->host->flags & ATA_HOST_NO_SSC) &&
(ap->host->flags & ATA_HOST_NO_DEVSLP)) {
- ata_port_dbg(ap, "no LPM states supported, not enabling LPM\n");
+ ata_port_warn(ap,
+ "No LPM states supported, forcing LPM max_power\n");
+ ap->flags |= ATA_FLAG_NO_LPM;
+ ap->target_lpm_policy = ATA_LPM_MAX_POWER;
return;
}
--
2.50.0
