Comment 40 for bug 231575

Hey,

   Is this a same bug? I am experiencing DVD drive related troubles in these months and it resembles our symptoms.

* Symptom
- DVD writing randomly fails (sometimes OK, sometimes bad)
- DVD drive reading frequently fails.
- Reading DVDs from ISO image are OK
- Trying DVD playing in Windows is OK
- Trying DVD reading/writing using USB-attached DVD drive is OK
- Some I/O error messages found in /var/log/messages, like this
Jun 16 20:27:16 <computer name> kernel: [62767.178851] end_request: I/O error, dev sr0, sector 45904

  Here is log messages after mounting DVD disk.
Jun 17 17:37:53 <computer name> kernel: [ 1705.024273] UDF-fs: Partition marked readonly
; forcing readonly mount
Jun 17 17:37:53 <computer name> kernel: [ 1705.052214] UDF-fs INFO UDF 0.9.8.1 (2004/29/
09) Mounting volume 'PCBE_53310', timestamp 2009/04/13 12:41 (121c)
Jun 17 17:38:17 <computer name> kernel: [ 1723.589345] cdb a4 00 00 00 00 00 00
 00 00 10 c1 00 00 00 00 00
Jun 17 17:38:17 <computer name> kernel: [ 1723.589346] res 40/00:02:00:0c:00/00
:00:00:00:00/a0 Emask 0x4 (timeout)
Jun 17 17:38:18 <computer name> kernel: [ 1723.803249] ata1: soft resetting link
Jun 17 17:38:23 <computer name> kernel: [ 1727.400009] ata1: port is slow to respond, pl
ease be patient (Status 0xf8)
Jun 17 17:38:28 <computer name> kernel: [ 1731.269685] ata1: hard resetting link
Jun 17 17:38:28 <computer name> kernel: [ 1731.654005] ata1: SATA link up 1.5 Gbps (SSta
tus 113 SControl 310)
Jun 17 17:38:28 <computer name> kernel: [ 1731.912704] ata1.00: configured for UDMA/66
Jun 17 17:38:28 <computer name> kernel: [ 1731.912724] ata1: EH complete
Jun 17 17:38:28 <computer name> kernel: [ 1731.914444] sr0: disc change detected.
Jun 17 17:38:28 <computer name> kernel: [ 1731.922459] VFS: busy inodes on changed media.

* current workaround
  Disabling DMA feature.
- add
    options libata dma=1
  in /etc/modprobe.d/options
- Then,
  sudo cp /boot/initrd.img-`uname -r` /boot/initrd.img-`uname -r`.bak
  sudo mkinitramfs -o /boot/initrd.img-`uname -r`

   After reboot, the system is OK and I can read/write DVD with no problem. However, as DMA mode is off, the DVD playing is really slow and glitchy.

* System
- Coumputer: Dell OptiPlex 740
- CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 5000+
- Peripheral chip: nVidia C51
  My system has internal additional SATA interface attached in the PCI bus. It uses Sil 3512 chipset. The DVD drive is attached to this SATA card.

    I hope this message helps.