2.6.19-rc1: libata PATA CDROM poor performance

[Alistair John Strachan <s0348365@sms.ed.ac.uk>]

Alan,

I've been experimenting with your PATA drivers again on 2.6.19-rc1. I notice 
that optical drives don't seem to behave correctly. I can't tell what the 
exact problem is, but if I put a CD in, the drive never really spins up, and 
read performance is very poor (~3.0MB/s).

Any ideas?

pata_amd 0000:00:06.0: version 0.2.4
PCI: Setting latency timer of device 0000:00:06.0 to 64
ata5: PATA max UDMA/133 cmd 0x1F0 ctl 0x3F6 bmdma 0xE800 irq 14
ata6: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xE808 irq 15
scsi4 : pata_amd
ata5.00: ATAPI, max UDMA/33
ata5.00: configured for UDMA/33
scsi5 : pata_amd
ATA: abnormal status 0x8 on port 0x177
scsi 4:0:0:0: CD-ROM            _NEC     DVD_RW ND-4570A  1.03 PQ: 0 ANSI: 5
sr0: scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray
Uniform CD-ROM driver Revision: 3.20
sr 4:0:0:0: Attached scsi CD-ROM sr0

(OTOH, I tried putting a damaged CD in the drive and the error handling on the 
new libata PATA code is marvellous. I was able to unmount and eject the disk 
within a couple of seconds of the first media error, a vast improvement over 
the CONFIG_IDE alternative..)

-- 
Cheers,
Alistair.

Final year Computer Science undergraduate.
1F2 55 South Clerk Street, Edinburgh, UK.
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