Graceful way to spin down (unload head) USB attached mobile hard drive BEFORE shutdown(poweroff/reboot/halt)

wlmqljj · 15 October 2024 03:05

After some digging into the code.
I probably find the reason why the usb-storage, uas, and some sas driver do not handle this.
Driver need to operate generic devices, maybe the chip itself handling spindown must be the proper way. Sadly, chip manufactures often have their unique quirks.
Such as this Asmedia chip asm1135.
But if Chips do not handle this as a routine, then the driver should take responsibility to tackle with it.
I found the commit Damien Le Moal did last year for Firewire. It clearly show this type of device configuration need to be done within low level driver.

github.com

torvalds/linux/blob/eca631b8fe808748d7585059c4307005ca5c5820/drivers/firewire/sbp2.c#L1509-L1539


      
          static int sbp2_scsi_device_configure(struct scsi_device *sdev,
          		struct queue_limits *lim)
          {
          	struct sbp2_logical_unit *lu = sdev->hostdata;
          
          	sdev->use_10_for_rw = 1;
          
          	if (sbp2_param_exclusive_login) {
          		sdev->manage_system_start_stop = 1;
          		sdev->manage_runtime_start_stop = 1;
          		sdev->manage_shutdown = 1;
          	}
          
          	if (sdev->type == TYPE_ROM)
          		sdev->use_10_for_ms = 1;
          
          	if (sdev->type == TYPE_DISK &&
          	    lu->tgt->workarounds & SBP2_WORKAROUND_MODE_SENSE_8)
          		sdev->skip_ms_page_8 = 1;

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So as to usb-storage and uas, need to add

sdev->manage_runtime_start_stop = 1;
sdev->manage_shutdown = 1;

as well in their configuration.
For usb-storage:

github.com

torvalds/linux/blob/eca631b8fe808748d7585059c4307005ca5c5820/drivers/usb/storage/scsiglue.c#L91-L329


      
          static int device_configure(struct scsi_device *sdev, struct queue_limits *lim)
          {
          	struct us_data *us = host_to_us(sdev->host);
          	struct device *dev = us->pusb_dev->bus->sysdev;
          
          	/*
          	 * Many devices have trouble transferring more than 32KB at a time,
          	 * while others have trouble with more than 64K. At this time we
          	 * are limiting both to 32K (64 sectores).
          	 */
          	if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
          		unsigned int max_sectors = 64;
          
          		if (us->fflags & US_FL_MAX_SECTORS_MIN)
          			max_sectors = PAGE_SIZE >> 9;
          		lim->max_hw_sectors = min(lim->max_hw_sectors, max_sectors);
          	} else if (sdev->type == TYPE_TAPE) {
          		/*
          		 * Tapes need much higher max_sector limits, so just
          		 * raise it to the maximum possible (4 GB / 512) and

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For uas:

github.com

torvalds/linux/blob/eca631b8fe808748d7585059c4307005ca5c5820/drivers/usb/storage/uas.c#L835-L901


      
          static int uas_device_configure(struct scsi_device *sdev,
          		struct queue_limits *lim)
          {
          	struct uas_dev_info *devinfo = sdev->hostdata;
          
          	if (devinfo->flags & US_FL_MAX_SECTORS_64)
          		lim->max_hw_sectors = 64;
          	else if (devinfo->flags & US_FL_MAX_SECTORS_240)
          		lim->max_hw_sectors = 240;
          
          	if (devinfo->flags & US_FL_NO_REPORT_OPCODES)
          		sdev->no_report_opcodes = 1;
          
          	/* A few buggy USB-ATA bridges don't understand FUA */
          	if (devinfo->flags & US_FL_BROKEN_FUA)
          		sdev->broken_fua = 1;
          
          	/* UAS also needs to support FL_ALWAYS_SYNC */
          	if (devinfo->flags & US_FL_ALWAYS_SYNC) {
          		sdev->skip_ms_page_3f = 1;

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Other driver also need similar change to adapt Damien Le Moal changed last year.

I did made some mod in kernel for my own use. But I have never post a patch to kernel mailing list, I think it is not a easy thing to start.
So if someone is experienced and willing to make a patch for upstream kernel driver, I will be appreciated!

For average user who using kernel version 6.1 and beyond, as Harddisk spin down on shutdown no longer works mentioned.
Apply udev rule

ACTION=="add|change", DRIVERS=="usb-storage|uas", SUBSYSTEM=="scsi_disk", ATTR{manage_runtime_start_stop}="1", ATTR{manage_shutdown}="1"

is enough according to linux/drivers/ata/libata-scsi.c at eca631b8fe808748d7585059c4307005ca5c5820 · torvalds/linux · GitHub

For user using kernel before 6.1, apply the old udev rule.

ACTION=="add|change", DRIVERS=="usb-storage|uas", SUBSYSTEM=="scsi_disk", ATTR{manage_start_stop}="1"