Re: 2.6.26 DVD playing regression with libata

[Justin Mattock]

On Tue, Jul 29, 2008 at 11:57 PM, Tvrtko A. Ursulin <tvrtko@xxxxxxxxxxx> wrote:
> On Wednesday 30 July 2008 00:20:11 Alan Cox wrote:
>> > Jul 29 21:10:03 media kernel: [353032.319013] sr 2:0:0:0: [sr0] unaligned
>> > transfer Jul 29 21:10:03 media kernel: [353032.319013] sr 2:0:0:0: [sr0]
>> > unaligned transfer
>>
>> This is coming from the scsi/block layer and definitely isn't good.
>> Doesn't directly look like a libata bug but seems to be higher up the
>> stack. What software is triggering this ?
>
> I tried to reproduce it now but could not.
>
> After a fresh boot into 2.6.26, I first tried mounting the DVD which was fine. Then I ran lsdvd which also worked and finally mplayer without any problems. In
> contrast to that yesterday I ran my playdvd.pl (http://www.ursulin.net/2008/06/effectively-using-mplayer-within-mythtv/) script from within MythTV and it
> exited immediately. It looked like either it triggered that failure without any delay or subsystem was already in that failure mode by simple DVD insertion.
> When ran directly lsdvd would exit being unable to open /dev/dvd (/dev/scdo). Unfortunately I didn't debug it further at the time.
>
> The only difference is that yesterday box had an uptime of couple of days while this morning it was completely fresh. Unless mounting the disc before
> everything else somehow stabilised something. Hm let me do another reboot... no, still can't reproduce it.
>
> One interesting thing, sometimes it detects drive capabilities like this:
> [    3.498951] sr0: scsi3-mmc drive: 62x/62x writer dvd-ram cd/rw xa/form2 cdda tray
>
> And sometimes like this:
> [    3.514104] sr0: scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray
>
> Later I think is correct according to drive datasheet.
>
> I will keep 2.6.26 running and see if the problem comes back in following days.
>
> Tvrtko
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I usually see these errors with mplayer i.g. insert a dvd
then press play instead of waiting for the dvd to settle down.

-- 
Justin P. Mattock
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