Re: Problem Setting DMA

["Thomas H. George" <tom@spininternet.com>]

On Sat, Apr 30, 2005 at 08:15:51PM +0100, Dave Ewart wrote:
> On Saturday, 30.04.2005 at 11:27 -0400, Thomas H. George wrote:
> 
> > On Fri, Apr 29, 2005 at 10:26:49PM +0100, Dave Ewart wrote:
> > > On Friday, 29.04.2005 at 22:24 +0200, Sven Arvidsson wrote:
> > > 
> > > > Thomas H. George wrote:
> > > > > The result of lspci is:
> > > > >
> > > > > 0000:00:11.1 IDE interface: VIA Technologies, Inc.
> > > > > VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
> > > > > 0000:00:11.5 Multimedia audio controller: VIA Technologies, Inc.
> > > > 
> > > > and
> > > > 
> > > > > # CONFIG_BLK_DEV_VIA82CXXX is not set
> > > > 
> > > > That doesn't look good.
> > > 
> > > Indeed.  That may be the only thing you're missing.  But, the question
> > > arises as to why this option is not set.  Did you intentionally disable
> > > it, or did you start with a completely bare config?
> > > 
> > Astounding!!! - CONFIG_BLK_DEV_VIA82CXXX does not exist!
> 
> Erm, but you've just shown us it in your config?  If you can't find the
> options to set it, then something is very wrong.
> 
> > Normally I keep a copy of .config in the file /usr/src/konfig-2.6.8 and
> > this is the file which was included in my last message.  I ran
> > menuconfig to try to set CONFIG_BLK_DEV_VIA82CXXX and could not find it.
> > I stepped through make config and could not find it.  Now the two files
> > /usr/src/konfig-2.6.8 and /usr/src/kernel-source-2.6.8/.config are
> > different and the former contains many more bug fix files than the
> > latter.  I am attaching the relevant sections of the two files in the
> > hope that you might figure out what I have done wrong.
> 
> It really, really sounds like you've managed to screw up your kernel
> config.  The above behaviour suggests that you might have forgotten to
> do a 'make oldconfig' at some stage ... also note that 'make config' and
> 'make menuconfig' might leave your .config files written slightly
> differently.  They should have the same *contents*, ultimately, but
> perhaps laid out in a different way.
> 
> Please persist in trying to get a Debian stock kernel working; this
> sounds like your best bet.
> 
Many thanks for your help as I bumbled my way through this problem.

After finding the difference between my konfig file and my .config file
I copied the former back over the .config, stepped through make config
and was able to enable CONFIG_BLK_DEV_VIA82CXXX.  I compiled a new
kernel and found hdparm -d 1 /dev/hdb turned on dma with no problem.

Subsequently I ran make menuconfig and found it now included all the
choices that were in konfig.

So the problem is solved although I have no idea why some of the options
had disappeared from .config.

Tom