Re: hotplug works, but newly plug not

[Ming Zhang <mingz@ele.uri.edu>]

On Wed, 2006-05-24 at 13:51 -0700, Tejun Heo wrote:
> Ming Zhang wrote:
> > Hi All
> > 
> > I use the libata patch from
> > http://home-tj.org/wiki/index.php/Libata-tj-stable with my supermicro MB
> > ( ICH7R chip). The AHCI works as desired in most of the time.
> > 
> > If I have disk(s) plugged in during boot. Then after boot, I kept unplug
> > and plug many times and it works fine.
> > 
> > but i noticed that if I have the disk(s) unplugged during boot, then
> > after boot, I plug the disk and nothing shows. if I try to do rescan by
> > run the rescan lun script, i saw these from dmesg.
> > 
> > Anything clue ? Thanks!
> > 
> > Ming
> > 
> > ---------------------------------------
> > ata4: soft resetting port
> > ata4: SATA link down (SStatus 0 SControl 0)
> > ata4: EH complete
> > ata3: soft resetting port
> > ata3: SATA link down (SStatus 0 SControl 0)
> > ata3: EH complete
> > ata4: soft resetting port
> > ata4: SATA link down (SStatus 0 SControl 0)
> > ata4: EH complete
> > ata3: soft resetting port
> > ata3: SATA link down (SStatus 0 SControl 0)
> > ata3: EH complete
> > ata4: soft resetting port
> > ata4: SATA link down (SStatus 0 SControl 0)
> > ata4: EH complete
> 
> Hello,
> 
> That never happened to me on AHCI mode but I experienced similar thing 
> with piix mode.  It might be that your BIOS doesn't turn on PCS enable 

the BIOS has a option to switch between AHCI and PIIX. So I guess the
reason is as you said.

also this is kernel boot log related to this. could u point out the
place for this pcs in AHCI spec? i just printed AHCI and can not find
related information about this PCS. the code operate at offset 0x92 but
i can not find anything about that.


libata version 1.30 loaded.
ahci 0000:00:1f.2: version 1.3
ACPI: PCI Interrupt 0000:00:1f.2[B] -> GSI 19 (level, low) -> IRQ 19
ahci 0000:00:1f.2: pcs 0x11->0x1f
PCI: Setting latency timer of device 0000:00:1f.2 to 64
ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0x1 impl SATA
mode
ahci 0000:00:1f.2: flags: 64bit ncq pm led clo pio slum part
ata1: SATA max UDMA/133 cmd 0xF881C500 ctl 0x0 bmdma 0x0 irq 19
ata2: SATA max UDMA/133 cmd 0xF881C580 ctl 0x0 bmdma 0x0 irq 19
ata3: SATA max UDMA/133 cmd 0xF881C600 ctl 0x0 bmdma 0x0 irq 19
ata4: SATA max UDMA/133 cmd 0xF881C680 ctl 0x0 bmdma 0x0 irq 19
scsi0 : ahci
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: cfg 49:2f00 82:74eb 83:7feb 84:4123 85:74e9 86:3c03 87:4123
88:007f
ata1.00: ATA-7, max UDMA/133, 781422768 sectors: LBA48
ata1.00: configured for UDMA/133
scsi1 : ahci
ata2: SATA link down (SStatus 0 SControl 0)
scsi2 : ahci
ata3: SATA link down (SStatus 0 SControl 0)
scsi3 : ahci
ata4: SATA link down (SStatus 0 SControl 0)
  Vendor: ATA       Model: HDS724040KLSA80   Rev: KFAO
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sda: 781422768 512-byte hdwr sectors (400088 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
SCSI device sda: 781422768 512-byte hdwr sectors (400088 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
 sda:
sd 0:0:0:0: Attached scsi disk sda
sd 0:0:0:0: Attached scsi generic sg0 type 0




> bits for empty ports and thus the empty ports cannot be used after boot. 
> Can you try the attached patch?  (only compile-tested, be cautious)
> 
> plain text document attachment (patch)
> diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
> index 45fd71d..83751dd 100644
> --- a/drivers/scsi/ahci.c
> +++ b/drivers/scsi/ahci.c
> @@ -1306,6 +1306,15 @@ static int ahci_init_one (struct pci_dev
>  		have_msi = 0;
>  	}
>  
> +	{
> +		u8 orig_pcs, pcs;
> +		pci_read_config_byte(pdev, 0x92, &orig_pcs);
> +		pci_write_config_byte(pdev, 0x92, 0xf);
> +		pci_read_config_byte(pdev, 0x92, &pcs);
> +		dev_printk(KERN_INFO, &pdev->dev, "pcs 0x%x->0x%x\n",
> +			   orig_pcs, pcs);
> +	}
> +
>  	probe_ent = kmalloc(sizeof(*probe_ent), GFP_KERNEL);
>  	if (probe_ent == NULL) {
>  		rc = -ENOMEM;