What's with libata and DVDs ?

Attempting to play a known-good DVD-video in MythTV-0.21 using libata in kernel 2.6.27.7 :

sr 4:0:0:0: [sr0] unaligned transfer Buffer I/O error on device sr0, logical block 1080 Buffer I/O error on device sr0, logical block 1081 Buffer I/O error on device sr0, logical block 1082 Buffer I/O error on device sr0, logical block 1083 Buffer I/O error on device sr0, logical block 1084 Buffer I/O error on device sr0, logical block 1085 Buffer I/O error on device sr0, logical block 1086 Buffer I/O error on device sr0, logical block 1087 Buffer I/O error on device sr0, logical block 1088 sr 4:0:0:0: [sr0] unaligned transfer
sr 4:0:0:0: [sr0] unaligned transfer
sr 4:0:0:0: [sr0] unaligned transfer

This used to work back in 2.6.25 or so. Anyone else out there have similar DVD issues ?

-ml

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Mmm.. some DVDs play, others don't. I'll instrument the code and see if anything obvious pops up someday. Ignore me for now. :)

Your system somehow generated a scsi request which was not 2K aligned. The scsi mid layer then reported that and added padding - which presumably didn't help because the command shouldn't have been misaligned in the first place.

If you strace it do you see any misaligned requests coming from user space - also btw is the cd layer reporting the sector size wrong anywhere ?

Alan

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No complaints from the cd layer -- just that unaligned message. I've changed that message to actually *show* the values it is complaining about (what a concept, duh..), so next time I reproduce it there will be some information as to what was really going on.

Probably just a buggy app, or maybe 64-bit porting error in it.

Cheers