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Mon, 28 Jul 2025 16:25:01 +0000 Message-ID: Date: Mon, 28 Jul 2025 21:54:54 +0530 User-Agent: Mozilla Thunderbird Subject: Re: Regression on linux-next (next-20250708) To: Damien Le Moal CC: "intel-gfx@lists.freedesktop.org" , "intel-xe@lists.freedesktop.org" , , , , "Kurmi, Suresh Kumar" , "Saarinen, Jani" , References: <07563042-6576-41cd-9a95-de83cfc95de1@intel.com> Content-Language: en-GB From: "Borah, Chaitanya Kumar" In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MA5P287CA0024.INDP287.PROD.OUTLOOK.COM (2603:1096:a01:179::14) To SJ1PR11MB6129.namprd11.prod.outlook.com (2603:10b6:a03:488::12) Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PR11MB6129:EE_|IA1PR11MB6289:EE_ X-MS-Office365-Filtering-Correlation-Id: 74ca029e-5dc5-41b9-67f0-08ddcdf34d55 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014; 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[5][6] >> >> IIUC, the above change is based on spec and not something which can be >> reverted. So as I see it, we have to drop this code path for external ports. >> However I am not sure if we can achieve deep power states without enforcing it >> through the sysfs entry. >> >> Atleast for the basic-rte subtest, the test passes if we comment out the >> functions controlling the SATA ports. We will need more testing to determine if >> this approach work. Any thoughts on it? >> >> Also, are there other ways to detect a port is external other than receiving >> EOPNOTSUPP on the sysfs write? > > The attached patch adds the "link_power_management_supported" sysfs device > attribute for drives connected to AHCI. Would that work for you ? > Yes this could work. I quickly hacked the test to ignore writing policy if this file returns 0. Here is the state of the machine I am testing on. /sys/class/scsi_host/host0/link_power_management_supported: 0 /sys/class/scsi_host/host1/link_power_management_supported: 0 /sys/class/scsi_host/host2/link_power_management_supported: 0 /sys/class/scsi_host/host3/link_power_management_supported: 0 /sys/class/scsi_host/host4/link_power_management_supported: 1 /sys/class/scsi_host/host5/link_power_management_supported: 1 /sys/class/scsi_host/host6/link_power_management_supported: 1 /sys/class/scsi_host/host7/link_power_management_supported: 1 Regards Chaitanya > diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c > index 229429ba5027..495fa096dd65 100644 > --- a/drivers/ata/ata_piix.c > +++ b/drivers/ata/ata_piix.c > @@ -1089,6 +1089,7 @@ static struct ata_port_operations ich_pata_ops = { > }; > > static struct attribute *piix_sidpr_shost_attrs[] = { > + &dev_attr_link_power_management_supported.attr, > &dev_attr_link_power_management_policy.attr, > NULL > }; > diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c > index b335fb7e5cb4..c79abdfcd7a9 100644 > --- a/drivers/ata/libahci.c > +++ b/drivers/ata/libahci.c > @@ -111,6 +111,7 @@ static DEVICE_ATTR(em_buffer, S_IWUSR | S_IRUGO, > static DEVICE_ATTR(em_message_supported, S_IRUGO, ahci_show_em_supported, NULL); > > static struct attribute *ahci_shost_attrs[] = { > + &dev_attr_link_power_management_supported.attr, > &dev_attr_link_power_management_policy.attr, > &dev_attr_em_message_type.attr, > &dev_attr_em_message.attr, > diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c > index 0708686ca58a..82a1a72e47bf 100644 > --- a/drivers/ata/libata-sata.c > +++ b/drivers/ata/libata-sata.c > @@ -900,6 +900,18 @@ static const char *ata_lpm_policy_names[] = { > [ATA_LPM_MIN_POWER] = "min_power", > }; > > +static ssize_t ata_scsi_lpm_supported_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct Scsi_Host *shost = class_to_shost(dev); > + struct ata_port *ap = ata_shost_to_port(shost); > + > + return sysfs_emit(buf, "%d\n", !(ap->flags & ATA_FLAG_NO_LPM)); > +} > +DEVICE_ATTR(link_power_management_supported, S_IRUGO, > + ata_scsi_lpm_supported_show, NULL); > +EXPORT_SYMBOL_GPL(dev_attr_link_power_management_supported); > + > static ssize_t ata_scsi_lpm_store(struct device *device, > struct device_attribute *attr, > const char *buf, size_t count) > diff --git a/include/linux/libata.h b/include/linux/libata.h > index 1c0580627dbb..e9a6f37bd7f9 100644 > --- a/include/linux/libata.h > +++ b/include/linux/libata.h > @@ -547,6 +547,7 @@ typedef void (*ata_postreset_fn_t)(struct ata_link *link, > unsigned int *classes) > > extern struct device_attribute dev_attr_unload_heads; > #ifdef CONFIG_SATA_HOST > +extern struct device_attribute dev_attr_link_power_management_supported; > extern struct device_attribute dev_attr_link_power_management_policy; > extern struct device_attribute dev_attr_ncq_prio_supported; > extern struct device_attribute dev_attr_ncq_prio_enable; > >