On 9/5/23 14:49, Niklas Cassel wrote:
From: Niklas Cassel <niklas.cassel@xxxxxxx>
The target LPM policy can be set using either a Kconfig or a kernel module
parameter.
However, if the board type is set to anything but board_ahci_low_power,
then the LPM policy will overridden and set to ATA_LPM_UNKNOWN.
Additionally, if the default suspend is suspend to idle, depending on the
hardware capabilities of the HBA, ahci_update_initial_lpm_policy() might
override the LPM policy to either ATA_LPM_MIN_POWER_WITH_PARTIAL or
ATA_LPM_MIN_POWER.
All this means that it is very hard to know which LPM policy a user will
actually be using on a given system.
In order to make it easier to debug LPM related issues, print the LPM
policy on boot.
One common LPM related issue is that the device fails to link up.
Because of that, we cannot add this print to ata_dev_configure(), as that
function is only called after a successful link up. Instead, add the info
using ata_port_desc(). The port description is printed once during boot.
Before changes:
ata1: SATA max UDMA/133 abar m524288@0xa5780000 port 0xa5780100 irq 170
ata2: SATA max UDMA/133 abar m524288@0xa5780000 port 0xa5780180 irq 170
After changes:
ata1: SATA max UDMA/133 abar m524288@0xa5780000 port 0xa5780100 lpm-pol 4 irq 170
ata2: SATA max UDMA/133 abar m524288@0xa5780000 port 0xa5780180 lpm-pol 4 irq 170
Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
---
drivers/ata/ahci.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index abb5911c9d09..541f6ec7f395 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1898,6 +1898,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
ap->em_message_type = hpriv->em_msg_type;
ahci_update_initial_lpm_policy(ap, hpriv);
+ ata_port_desc(ap, "lpm-pol %d", ap->target_lpm_policy);
/* disabled/not-implemented port */
if (!(hpriv->port_map & (1 << i)))
Hmm. Not very instructive ('pol 4' ?).
Please use a string mapping here to translate it into something
human-readable.
Also one might consider a sysfs attribute to retrieve the information
from userspace.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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