linux-kernel - Re: [PATCH 1/2] ahci: Add PhyRdy Change control on actual LPM capability

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Message-ID: <244f0c98-13f4-1ac4-9ebe-facdad4ae8b6@opensource.wdc.com>
Date:   Thu, 21 Apr 2022 19:39:05 +0900
From:   Damien Le Moal <damien.lemoal@...nsource.wdc.com>
To:     Runa Guo-oc <RunaGuo-oc@...oxin.com>, linux-ide@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH 1/2] ahci: Add PhyRdy Change control on actual LPM
 capability

On 4/21/22 18:43, Runa Guo-oc wrote:
> On some platform, when OS enables LPM by default (eg, min_power),
> then, PhyRdy Change cannot be detected if ahci supports no LPM.

Do you mean "...if the ahci adapter does not support LPM." ?
If that is what you mean, then min_power should not be set. Mario has
patches to fix that.

> 
> In ahci spec, PhyRdy Change cannot coexist with LPM.
> 
> Adds support to control this case on actual LPM capability.
> 
> Signed-off-by: Runa Guo-oc <RunaGuo-oc@...oxin.com>
> ---
>  drivers/ata/ahci.c      | 9 +++++++++
>  drivers/ata/libata-eh.c | 4 ++++
>  include/linux/libata.h  | 4 ++++
>  3 files changed, 17 insertions(+)
> 
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index 397dfd2..03f0cb3 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -1870,6 +1870,15 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	else
>  		dev_info(&pdev->dev, "SSS flag set, parallel bus scan disabled\n");
>  
> +	if (hpriv->cap & HOST_CAP_PART)
> +		host->flags |= ATA_HOST_PART;
> +
> +	if (hpriv->cap & HOST_CAP_SSC)
> +		host->flags |= ATA_HOST_SSC;
> +
> +	if (hpriv->cap2 & HOST_CAP2_SDS)
> +		host->flags |= ATA_HOST_DEVSLP;
> +
>  	if (pi.flags & ATA_FLAG_EM)
>  		ahci_reset_em(host);
>  
> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
> index 3307ed4..05b1043 100644
> --- a/drivers/ata/libata-eh.c
> +++ b/drivers/ata/libata-eh.c
> @@ -3246,6 +3246,10 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
>  	unsigned int err_mask;
>  	int rc;
>  
> +	/* if controller does not support lpm, then sets no LPM flags*/
> +	if (!(ap->host->flags & (ATA_HOST_PART | ATA_HOST_SSC | ATA_HOST_DEVSLP)))
> +		link->flags |= ATA_LFLAG_NO_LPM;
> +
>  	/* if the link or host doesn't do LPM, noop */
>  	if (!IS_ENABLED(CONFIG_SATA_HOST) ||
>  	    (link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 732de90..7a243f4 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -216,6 +216,10 @@ enum {
>  	ATA_HOST_PARALLEL_SCAN	= (1 << 2),	/* Ports on this host can be scanned in parallel */
>  	ATA_HOST_IGNORE_ATA	= (1 << 3),	/* Ignore ATA devices on this host. */
>  
> +	ATA_HOST_PART		= (1 << 4), /* Host support partial.*/
> +	ATA_HOST_SSC		= (1 << 5), /* Host support slumber.*/
> +	ATA_HOST_DEVSLP		= (1 << 6), /* Host support devslp.*/
> +
>  	/* bits 24:31 of host->flags are reserved for LLD specific flags */
>  
>  	/* various lengths of time */


-- 
Damien Le Moal
Western Digital Research