Commit f7870e8d authored by Damien Le Moal's avatar Damien Le Moal Committed by Niklas Cassel
Browse files

ata: ahci: Disable DIPM if host lacks support 



The AHCI specification version 1.3.1 section 8.3.1.4 (Software
Requirements and Precedence) states that:

If CAP.SSC or CAP.PSC is cleared to ‘0’, software should disable
device-initiated power management by issuing the appropriate SET
FEATURES command to the device.

To satisfy this constraint and force ata_dev_configure to disable the
device DIPM feature, modify ahci_update_initial_lpm_policy() to set the
ATA_FLAG_NO_DIPM flag on ports that have a host with either the
ATA_HOST_NO_PART flag set or the ATA_HOST_NO_SSC flag set.

Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarNiklas Cassel <cassel@kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de.>
Link: https://lore.kernel.org/r/20250701125321.69496-7-dlemoal@kernel.org


Signed-off-by: default avatarNiklas Cassel <cassel@kernel.org>
parent 413e800c

drivers/ata/ahci.c

+7 −0
Original line number Diff line number Diff line
@@ -1780,6 +1780,13 @@ static void ahci_update_initial_lpm_policy(struct ata_port *ap) 
		return;

	}



	/* If no Partial or no Slumber, we cannot support DIPM. */

	if ((ap->host->flags & ATA_HOST_NO_PART) ||

	    (ap->host->flags & ATA_HOST_NO_SSC)) {

		ata_port_dbg(ap, "Host does not support DIPM\n");

		ap->flags |= ATA_FLAG_NO_DIPM;

	}



	/* If no LPM states are supported by the HBA, do not bother with LPM */

	if ((ap->host->flags & ATA_HOST_NO_PART) &&

	    (ap->host->flags & ATA_HOST_NO_SSC) &&