Re: [PATCH v2] ata: ahci: print the lpm policy on boot

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

On 9/6/23 18:22, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@wdc.com>
> 
> 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(), with the help of a new ata_port_desc_misc() helper.
> The port description is printed once per port 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 irq 170 lpm-pol 4
> ata2: SATA max UDMA/133 abar m524288@0xa5780000 port 0xa5780180 irq 170 lpm-pol 4
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>

Applied to for-6.7. Thanks !


-- 
Damien Le Moal
Western Digital Research