Symptoms: DVD drive read errors when trying to load live distros, or
play films under Linux.
For example:
SQUASHFS error: sb_bread failed reading block ...
SQUASHFS error: Unable to read page, block ..., size ...
end_request: I/O error, dev sr0, sector ...
Buffer I/O error on device sr0, logical block ...
Tests/Results: (I tried...)
(a) Ubuntu 7.04 'Fiesty Faun' (DVD) live boot
OK (Note: treats DVD-Drive as device hdc.)
(b) Ubuntu 8.04 'Hardy Heron' (DVD) live boot
BAD - errors like example above.
(c) Xubuntu 8.04 (CDR) live boot and media check
BAD - errors like example above.
(d) Ubuntu 8.10 'Intrepid Ibex' (DVD) live boot
BAD - but errored later, after failing to start X.
(e) Ubuntu 9.10 'Karmic Koala' (DVD) live boot
BAD - errors like example above.
(f) OpenSuse 10.2 (DVD) live boot and media check
OK
(g) OpenSuse 10.3 (DVD) live boot and media check
BAD
(h) OpenSuse 11.0 (DVD) live boot and media check
OK! A later version that works?!
(i) OpenSuse 11.1 (DVD) live boot
BAD
(j) OpenSuse 11.2 (DVD) live boot
BAD
(k) Knoppix 5.3.1
OK (Note: although kernel is late-ish 2.6.24.2 it still treats CD as device
hdc...)
NOTE: Disks that do not work in the Test System DO work in a more modern
PC...
Test System:
Advent 5480DVD
[SiS Chipset]
[Old circa 2000, PIII (Coppermine) 800MHz]
BIOS circa 2001
RAM upgraded to 512MB
DVD upgraded to Pioneer DVR KD08 (this is only 8months old from manufacture)
HDD upgraded to 40GB
Things tried that *DID* *NOT* solve problem:
- Used 'regionset' utility to set region on the new DVD drive.
- Apply kernel parameters mix'n'match of the following:
generic.all_generic_ide=1
irqpoll
ide=nodma
apic=off
- Memory test - shows my SDRAMs are good.
Media Check Experiment:
Aborting install of OpenSuse 10.2 we get a menu including the media check
option.
If I swap DVD for e.g. 10.3 then select this option, it successfully verifies
DVD, even though 10.3 will not verify *itself* successfully. That is, aborting
10.3 install and doing media check on itself fails!
i.e. the Linux SW version running the media dictates whether the DVD works, not
a media problem.
Windows Experiment:
Replace HDD with old HDD with Windows ME (!) on.
This can successfully play DVD movies.
After this, which confirms the region setting, the Linux DVD behaviour is no
different - same problems.
(So the dead Windows ME or *old* Linux are my best bet for playing DVDs on this
HW?!?! Both are security risks so such a machine could NOT be connected to the
net.)
Experimental Conclusions:
- There is nothing wrong with the media - it must be accepted that at least
most of them are good - in fact I think they all are.
- There is nothing wrong with the DVD drive.
- There is nothing wrong with the computer HW in general.
- There *IS* something wrong with (newer) Linux DVD/CD driver SW on this HW...
- ... - it is emergent on more recent Linux SW versions, possibly when IDE got
wrapped to make it look like SCSI.
+++ Workaround Solution +++ :
After all else failed I finally find the libata.dma kernel parameter works when
excluding DMA on CD i.e. [in the following manner]
(***Works on Ubuntu 9.10 'Karmic'***)
libata.dma=1
[or =5, the point here is to exclude 2=CD DMA from the bitmask]
Unfortunately OpenSuse 11.2 'Kiwi' bootloader does not understand this
option....so still no way in.
Summary:
I have a work-around solution for this kind of HW.
But it will be suboptimal - no DMA on CD/DVD.
And (I believe the evidence points to) something that used to work got (has
gotten) broke.
It is *NOT* broken HW (in the broad sense, the DVD works with older Linux and
with Windows.)
My understanding is something like the old IDE modules got replaced by libata,
sr_mod etc.(?)
So this would be suspect.
I would suggest this form of this error needs a fix - that either this
bug is reopened or a one one opened.
--
SQUASHFS error while booting from live cd
https://bugs.launchpad.net/bugs/172937
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