libata: 30sec delay during boot with cdrom attached

libata: 30sec delay during boot with cdrom attached

[Gregor Jasny]

Hi,

after switching to libata on my old Dell notebook, I get a 30 seconds
long delay during boot. If I remove the CDROM the boot process is as
fast as with the old ide driver.

Boot with cdrom:
[   28.103034] ata_piix 0000:00:07.1: version 2.00ac7
[   28.103234] ata1: PATA max UDMA/33 cmd 0x1F0 ctl 0x3F6 bmdma 0x860 irq 14
[   28.103841] ata2: PATA max UDMA/33 cmd 0x170 ctl 0x376 bmdma 0x868 irq 15
[   28.104535] scsi0 : ata_piix
[   28.263015] ata1.00: ATA-7, max UDMA/100, 78242976 sectors: LBA48
[   28.263486] ata1.00: ata1: dev 0 multi count 8
[   28.269671] ata1.00: configured for UDMA/33
[   28.270001] scsi1 : ata_piix
^-- Hangs here
[   58.594321] ata2.00: ATAPI, max UDMA/33
[   58.754241] ata2.00: configured for UDMA/33
[   58.754852] scsi 0:0:0:0: Direct-Access     ATA      SAMSUNG
MP0402H  UC10 PQ: 0 ANSI: 5
[   58.755787] SCSI device sda: 78242976 512-byte hdwr sectors (40060 MB)
[   58.756312] sda: Write Protect is off
[   58.756595] sda: Mode Sense: 00 3a 00 00
[   58.756657] SCSI device sda: write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[   58.757459] SCSI device sda: 78242976 512-byte hdwr sectors (40060 MB)
[   58.757976] sda: Write Protect is off
[   58.758258] sda: Mode Sense: 00 3a 00 00
[   58.758318] SCSI device sda: write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[   58.758984]  sda: sda1 sda2 sda3 sda4
[   59.212482] sd 0:0:0:0: Attached scsi disk sda
[   59.213005] sd 0:0:0:0: Attached scsi generic sg0 type 0
[   59.213930] scsi 1:0:0:0: CD-ROM            SAMSUNG  CD-ROM SN-124
  N102 PQ: 0 ANSI: 5
[   59.236734] sr0: scsi3-mmc drive: 24x/24x cd/rw xa/form2 cdda tray
[   59.252814] Uniform CD-ROM driver Revision: 3.20
[   59.269038] sr 1:0:0:0: Attached scsi CD-ROM sr0
[   59.269228] sr 1:0:0:0: Attached scsi generic sg1 type 5

My notebook has a PIIX4 controller:
IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)

This happens with all libata enabled kernels including the latest git
snapshot (2.6.21-rc2).

Can anyone shed some light on this?

Thanks,
Gregor

PS: As far as I remember this cdrom was blacklisted for DMA or
whatever reasons in early Linux 2.6 kernels.