Re: [PATCH] pm80xx: Fix hibernation issue

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Mon, 2014-06-16 at 15:30 -0400, bradley.grove@gmail.com wrote:
> From: Bradley Grove <bgrove@attotech.com>
> 
> During hibernation, the HBA firmware may lose power and forget the device
> id info.   This causes the HBA to reject IO upon resume.   The fix is
> to call the libsas power management routines to make the domain device
> forgetful.
> 
> This patch also changes the value of pm8001_flags during resume to allow
> completions to work.
> 
> This fixes bug 76681: https://bugzilla.kernel.org/show_bug.cgi?id=76681
> 
> Signed-off-by: Bradley Grove <bgrove@attotech.com>
> ---
>  drivers/scsi/pm8001/pm8001_init.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
> index c4f31b21..9f51a1f 100644
> --- a/drivers/scsi/pm8001/pm8001_init.c
> +++ b/drivers/scsi/pm8001/pm8001_init.c
> @@ -957,6 +957,7 @@ static int pm8001_pci_suspend(struct pci_dev *pdev, pm_message_t state)
>  	int  i, j;
>  	u32 device_state;
>  	pm8001_ha = sha->lldd_ha;
> +	sas_suspend_ha(sha);
>  	flush_workqueue(pm8001_wq);
>  	scsi_block_requests(pm8001_ha->shost);
>  	if (!pdev->pm_cap) {
> @@ -1026,7 +1027,7 @@ static int pm8001_pci_resume(struct pci_dev *pdev)
>  	rc = pci_go_44(pdev);
>  	if (rc)
>  		goto err_out_disable;
> -
> +	sas_prep_resume_ha(sha);
>  	/* chip soft rst only for spc */
>  	if (pm8001_ha->chip_id == chip_8001) {
>  		PM8001_CHIP_DISP->chip_soft_rst(pm8001_ha);
> @@ -1058,7 +1059,12 @@ static int pm8001_pci_resume(struct pci_dev *pdev)
>  		for (i = 1; i < pm8001_ha->number_of_intr; i++)
>  			PM8001_CHIP_DISP->interrupt_enable(pm8001_ha, i);
>  	}
> +	pm8001_ha->flags = PM8001F_INIT_TIME;
>  	scsi_unblock_requests(pm8001_ha->shost);
> +	pm8001_scan_start(pm8001_ha->shost);
> +	msleep(100);

What's the reason for the 0.1s sleep?  Something tells me it's to try to
ensure that all the work kicked off by the scan start is completed in
which case a sleep seems to be a bit racy.

James

> +	sas_resume_ha(sha);
> +	pm8001_ha->flags = PM8001F_RUN_TIME;
>  	return 0;
>  
>  err_out_disable: