DMA issues with FC4 on a Dell precision M70

[Robin Laing]

François Patte wrote:
> Alfredo Ferrari wrote:
> 
>>Yes
>>
>>my PATA disk is the master on the second IDE channel (hdc). This is
>>actually the laptop modular bay where I can insert the DVD/2nd hard
>>drive/2nd battery. The same disk in the same bay on the same channel
>>of a D800 (where the primary disk is PATA and not SATA as in the M70)
>>works nicley with DMA enabled at boot time.
>>
>>Unfortunately it seems to be a known Linux kernel bug/limitation (see
>>https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=163418 )
>>a rather frustrating one I must say.
> 
> 
> I don't know much about this, but I came accross this problem for
> playing dvd with xine.
> 
> It seems to me that the problem occurs on laptop with sata hd: there is
> a single controller for both ide drive and sata disk and you cannot set
> the dma.
> 
> This problem does not occur with desktop where you have ide controller.
> 
> I have two solutions for this:
> 
> 1- hdparm -c1 /dev/hdc
> 
> You can watch dvd in a better way (not perfect)
> 
> 2- rip the dvd to the hard drive with dvdbackup and watch them (perfect)
> 
> Hope this help.
> 

Been away for a week so I am late responding.

Having had similar problems on a Toshiba laptop with an Intel ICH6 
controller.  Could not get DVD's to play and could not get DMA to work.

I can now play DVD's perfectly from my DVD player.  I played with the 
  'options libata atapi_enabled=1' settings and the latest kernel 
seems to have all working.  I would have to look at the laptop to see 
the exact changes (at home).  I could not get that libata settings to 
work at first.

I know that the changes did not work in grub but I had to play with 
the module config files.

It was also recommended to look at possible bios settings.
-- 
Robin Laing