Re: [preview] Latest AMD & VIA IDE drivers with UDMA100 support

[Alan Chandler]

On Sat, 20 Jan 2001 20:18:34 -0500 (EST), you wrote:

>that's not the topic: Andre's talking about pci-clock-based timing
>constants the the driver programs into the ide controller - a matter
>of an extra few/more nanoseconds.

I know, but when looking hard for a problem in one place and not
finding it, it is sometimes helpful to consider other options.

I am getting errors under 2.4.0 which didn't appear in 2.2.17 - and as
far as I could see from hdparm - both were at UDMA mode 2 (I assume
thats what the * means - the man page wasn't very clear).  My drives
only handle up to this mode, and I was wondering if the new driver was
trying to run them at a mode higher than they were supposed to go.

This massive difference in timing  seemed significant.
>
>quite slow in either case, at least for modern hardware (which is 
>all in the 20-40 MB/s range).  this looks like a PIO vs DMA difference
>to me, not even UDMA.  of course, hdparm can tell you what mode you're in.
>

I did discover a difference - 2.2.17 set the drives with multisector
off, 2.4.0 was setting multisector on.  However, I have redone the
timing with multisector turned on in the 2.2.17 case and the
difference is still there.

Under 2.2.17 with multisector turned on

/dev/hda:

 Model=IBM-DHEA-38451, FwRev=HP8OA20C, SerialNo=SH0SH0X1795
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=28
 BuffType=3(DualPortCache), BuffSize=472kB, MaxMultSect=16,
MultSect=16
 DblWordIO=no, OldPIO=2, DMA=yes, OldDMA=2
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=16514064
 tDMA={min:120,rec:120}, DMA modes: sword0 sword1 sword2 mword0 mword1
mword2 
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, PIO modes: mode3 mode4 
 UDMA modes: mode0 mode1 *mode2 

------------------

/dev/hda:
 Timing buffered disk reads:  64 MB in 19.88 seconds =  3.22 MB/sec

Under 2.4.0

/dev/hda:

 Model=IBM-DHEA-38451, FwRev=HP8OA20C, SerialNo=SH0SH0X1795
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=28
 BuffType=3(DualPortCache), BuffSize=472kB, MaxMultSect=16,
MultSect=16
 DblWordIO=no, OldPIO=2, DMA=yes, OldDMA=2
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=16514064
 tDMA={min:120,rec:120}, DMA modes: sword0 sword1 sword2 mword0 mword1
mword2 
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, PIO modes: mode3 mode4 
 UDMA modes: mode0 mode1 *mode2 

------------------

/dev/hda:
 Timing buffered disk reads:  64 MB in  6.58 seconds =  9.73 MB/sec

I don't suppose the fact that my hdparm is oldish (3.6 I think) have
any bearing on this?
Alan

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