Re: PATA DMA problem leading to kernel panic on reading movie DVDs

[Borislav Petkov]

Hi,

On Sun, May 17, 2009 at 11:12:24AM +0200, Martin Lottermoser wrote:
> Hello,
> 
> newer versions of the Linux kernel overestimate my DVD drive's
> DMA capabilities, leading either to DMA being disabled or a kernel
> panic.
> 
> My setup is:
> 
>   Motherboard: ASUS P4C800-E Deluxe
>     South bridge: ICH5R
>       IDE Interface Controller (PATA): Intel 82801EB/ER (PCI: 8086:24db)
>   DVD drive: Samsung SH-S202N, attached as hdc.
>     There is also an older CD writer (Lite-On LTR-52327S) attached as
>     hdd.
>   Operating system: Debian 5.0.0 with security updates
> 
> On upgrading from Debian 4.0 (Linux 2.6.18) to 5.0 (Linux 2.6.26) I
> found that trying to play movie DVDs with vlc (VideoLAN media player)
> led to DMA being disabled:
> 
>   hdc: cdrom_decode_status: status=0x51 { DriveReady SeekComplete Error }
>   hdc: cdrom_decode_status: error=0x40 { LastFailedSense=0x04 }
>   ide: failed opcode was: unknown
>   <4 more identical groups of these messages>
>   hdc: DMA disabled
>   hdc: ide_intr: huh? expected NULL handler on exit
>   hdc: ATAPI reset complete
> 
> The resulting configuration is too slow to play movies. I booted the
> older kernel and everything was fine.
> 
> I then tested various versions of the Linux kernel where I happened to
> have the original sources. The most interesting results were:
> 
>   2.6.22.9      works, no errors visible in syslog
>   2.6.23.14     works, but syslog shows an error (see below)
>   2.6.24.3	DMA disabled
>   2.6.29.3	Kernel panic: Fatal exception in interrupt (ide_intr)
>                 on trying to open the DVD with vlc

can you catch that kernel panic on another machine through serial
console/netconsole and send it to me, please?

Thanks.

-- 
Regards/Gruss,
    Boris.
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