On Thu, Sep 28, 2023 at 05:54:26PM +0200, Niklas Cassel wrote:
In AHCI 1.3.1, the register description for CAP.SSC: "When cleared to ‘0’, software must not allow the HBA to initiate transitions to the Slumber state via agressive link power management nor the PxCMD.ICC field in each port, and the PxSCTL.IPM field in each port must be programmed to disallow device initiated Slumber requests."
In AHCI 1.3.1, the register description for CAP.PSC: "When cleared to ‘0’, software must not allow the HBA to initiate transitions to the Partial state via agressive link power management nor the PxCMD.ICC field in each port, and the PxSCTL.IPM field in each port must be programmed to disallow device initiated Partial requests."
Ensure that we always set the corresponding bits in PxSCTL.IPM, such that a device is not allowed to initiate transitions to power states which are unsupported by the HBA.
DevSleep is always initiated by the HBA, however, for completeness, set the corresponding bit in PxSCTL.IPM such that agressive link power management cannot transition to DevSleep if DevSleep is not supported.
sata_link_scr_lpm() is used by libahci, ata_piix and libata-pmp. However, only libahci has the ability to read the CAP/CAP2 register to see if these features are supported. Therefore, in order to not introduce any regressions on ata_piix or libata-pmp, create flags that indicate that the respective feature is NOT supported. This way, the behavior for ata_piix and libata-pmp should remain unchanged.
This change is based on a patch originally submitted by Runa Guo-oc.
Signed-off-by: Niklas Cassel niklas.cassel@wdc.com Fixes: 1152b2617a6e ("libata: implement sata_link_scr_lpm() and make ata_dev_set_feature() global") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal dlemoal@kernel.org (cherry picked from commit 24e0e61db3cb86a66824531989f1df80e0939f26) Signed-off-by: Niklas Cassel niklas.cassel@wdc.com
drivers/ata/ahci.c | 9 +++++++++ drivers/ata/libata-core.c | 19 ++++++++++++++++--- include/linux/libata.h | 4 ++++ 3 files changed, 29 insertions(+), 3 deletions(-)
Both now queued up, thanks.
greg k-h