[linux-audio-user] hdparm

[Mark Knecht]

Matt Barber wrote:
> So,
> 
> At home I had been getting some odd latency with my cd/dvd drive (using
> jack and alsaplayer, the sound would cut out for a split second, but
> with no xruns, so I'm thinking it was the drive or the ide channel, and
> not jack-related).  I have an nforce2-based motherboard, with a seagate
> SATA drive (nforce2 puts SATA on the primary master ide channel),
> another seagate ide drive, and a pioneer cd/dvd drive.  I keep all my
> soundfiles on the SATA drive (since it's supposed to be faster), and the
> linux system on the ide drive.  My previous setup gave the SATA drive
> the entire primary channel, put the system drive as secondary master and
> dvd as secondary slave.  I decided to try putting the system drive on
> the primary channel as slave, and giving the entire secondary channel to
> the dvd drive as master (this is a setup I have used successfully with
> other motherboards).  So - sound drive is hda, system drive is hdb, and
> dvd is hdc.  Here's the problem--  where I had been getting about
> 33-35MB/sec on both drives with the previous setup with hdparm -t, when
> I set it up like this, they both go down to about 6.5MB/sec.  This is
> because dma has been disabled - when I enable it on hdb (hdparm -d1
> /dev/hdb) the benchmark runs back up to around 35.  On hda, I can enable
> dma with no errors:
> 
> # hdparm -d1 /dev/hda
>  
> /dev/hda:
>  setting using_dma to 1 (on)
>  using_dma    =  1 (on)
> 
> but when I run the benchmark it's still around 6.5MB/sec, and then I
> notice that dma has again been disabled on BOTH hda and hdb.  Anybody
> know what the hell is going on here?  My guess is that the SATA-ide
> driver won't allow dma (or the default udma mode is wrong or something),
> and when the SATA drive gets its own ide channel, there's no problem -
> it's only when it's combined with other drives that there's a problem
> (it does the same when the cdrom is placed on primary/slave).
> 
> I'm getting fewer cutouts from the dvd drive (secondary master by
> itself) when I play a cd, but I'm still getting a few now and then - is
> there a way to optimize something here so I don't get them?
> 
> Thanks,
> 
> Matt
> 
> 

Matt,
    Not sure I can help, but I end up with a few questions from reading 
this. Maybe your answers will lead someone else to give you a good 
pointer. Mostly I'm confused about your hda/hdb comments with respect to 
  SATA drives which are normally on a cable by themselves. In my 
experience hda/hdb are the EIDE drive designations. With two controllers 
you then get hda-hdd for EIDE and hde for SATA.

    If you are really using EIDE drives then switching the order of the 
drives can be a problem *if* the drives were not configured for 
auto-detect *and* you forgot to chenge the jumpers. I don't know if this 
would cause the problem that you are seeing though.

    I think I'm just misunderstanding your setup. Maybe the NForce-2 
allows other options?  Not sure.

    I built a SATA machine for my dad about a year ago. (nforce? 
nforce-2? Don't remember) On his machine the SATA drive is hde. It has 
EIDE channels, and I used them for the CDRW drive, but it was a bit 
tricky getting it all configured. I shelled in remotely and got this info:

gandalf root # hdparm /dev/hde

/dev/hde:
  multcount    = 16 (on)
  IO_support   =  0 (default 16-bit)
  unmaskirq    =  0 (off)
  using_dma    =  1 (on)
  keepsettings =  0 (off)
  readonly     =  0 (off)
  readahead    =  8 (on)
  geometry     = 155061/16/63, sectors = 156301488, start = 0
gandalf root # hdparm -tT /dev/hde

/dev/hde:
  Timing buffer-cache reads:   1520 MB in  2.00 seconds = 760.00 MB/sec
  Timing buffered disk reads:  106 MB in  3.00 seconds =  35.33 MB/sec
gandalf root #

He is on a fairly old kernel:

gandalf root # uname -a
Linux gandalf 2.4.22-aa1 #8 Mon Aug 9 16:50:41 PDT 2004 i686 AMD 
Athlon(tm) XP 2500+ AuthenticAMD GNU/Linux
gandalf root #

and his grub.conf file:

default 2
timeout 20
splashimage=(hd0,1)/boot/grub/splash.xpm.gz

title=2.4.22-aa1
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1 ro root=/dev/hde3 hdg=none

title=2.4.22-aa1-20040507
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1-20040507 ro root=/dev/hde3 hdg=none

title=2.4.22-aa1-20040809
root (hd0,1)
kernel (hd0,1)/boot/bzImage-2.4.22-aa1-20040809 ro root=/dev/hde3 hdg=none

Don't know if any of this is going to help you so I'll shut up for now.

good luck,
Mark


    I can give you more data for that box if it's helpful, but maybe I 
need to better understand your setup.