On 7/31/23 09:39, Damien Le Moal wrote: > During system resume, ata_port_pm_resume() triggers ata EH to > 1) Resume the controller > 2) Reset and rescan the ports > 3) Revalidate devices > This EH execution is started asynchronously from ata_port_pm_resume(), > which means that when sd_resume() is executed, none or only part of the > above processing may have been executed. However, sd_resume() issues a > START STOP UNIT to wake up the drive from sleep mode. This command is > translated to ATA with ata_scsi_start_stop_xlat() and issued to the > device. However, depending on the state of execution of the EH process > and revalidation triggerred by ata_port_pm_resume(), two things may > happen: > 1) The START STOP UNIT fails if it is received before the controller has > been reenabled at the beginning of the EH execution. This is visible > with error messages like: > > ata10.00: device reported invalid CHS sector 0 > sd 9:0:0:0: [sdc] Start/Stop Unit failed: Result: hostbyte=DID_OK driverbyte=DRIVER_OK > sd 9:0:0:0: [sdc] Sense Key : Illegal Request [current] > sd 9:0:0:0: [sdc] Add. Sense: Unaligned write command > sd 9:0:0:0: PM: dpm_run_callback(): scsi_bus_resume+0x0/0x90 returns -5 > sd 9:0:0:0: PM: failed to resume async: error -5 > > 2) The START STOP UNIT command is received while the EH process is > on-going, which mean that it is stopped and must wait for its > completion, at which point the command is rather useless as the drive > is already fully spun up already. This case results also in a > significant delay in sd_resume() which is observable by users as > the entire system resume completion is delayed. > > Given that ATA devices will be woken up by libata activity on resume, > sd_resume() has no need to issue a START STOP UNIT command, which solves > the above mentioned problems. Do not issue this command by introducing > the new scsi_device flag no_start_on_resume and setting this flag to 1 > in ata_scsi_dev_config(). sd_resume() is modified to issue a START STOP > UNIT command only if this flag is not set. Martin, Are you OK with this patch ? Can I get your Acked-by please ? -- Damien Le Moal Western Digital Research
