[PATCH v2 09/10] ata: libata-core: Reduce the number of messages signaling broken LPM

[Damien Le Moal <dlemoal@kernel.org>]

ata_dev_config_lpm() prints the message "LPM support broken, forcing
max_power" for devices that have the ATA_QUIRK_NOLPM quirk flag set.
This messages is repeated for every device revalidation, which is not
necessary, but also erroneously printed for devices without a broken LPM
support when connected to a port that does not support LPM (e.g. because
the port is an external one with hotplug capability).

Since in all cases the device port target_lpm_policy is set to
ATA_LPM_MAX_POWER, avoid the "LPM broken" message repetition and
erroneous output by generating it only if the port target_lpm_policy is
not already set to ATA_LPM_MAX_POWER.

This change will suppress the "LPM broken" message for genuine cases of
a device having broken LPM if the initial LPM policy is set to
ATA_LPM_MAX_POWER through CONFIG_SATA_MOBILE_LPM_POLICY. This is not a
problem as the ATA_LPM_MAX_POWER policy implies that LPM is disabled and
unused, which is safe for devices with broken LPM.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libata-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index d1dff9018a3a..3e6cf26af4e4 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2819,7 +2819,8 @@ static void ata_dev_config_lpm(struct ata_device *dev)
 			dev->quirks |= ATA_QUIRK_NOLPM;
 	}
 
-	if (dev->quirks & ATA_QUIRK_NOLPM) {
+	if (dev->quirks & ATA_QUIRK_NOLPM &&
+	    ap->target_lpm_policy != ATA_LPM_MAX_POWER) {
 		ata_dev_warn(dev, "LPM support broken, forcing max_power\n");
 		ap->target_lpm_policy = ATA_LPM_MAX_POWER;
 	}
-- 
2.50.0