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

RunaGuo-oc
2022-04-22T09:57:26Z

On 2022/4/21 18:39, Damien Le Moal wrote:
> 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." ?

Yes.

> If that is what you mean, then min_power should not be set.

Yes, I agree with you. But, as we know, link_power_management
is a user policy which can be modified, if some users are not
familiar with ahci spec, then the above case may happen.

> Mario has patches to fix that.

Hmm. How to patch this case ?

>> 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@zhaoxin.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 */
>