Heavy disc writes (eg. unzipping linux kernel source) cause the system
processor usage (as reported by top/xosview) to jump to 100%, making
the X mouse/audio freeze etc.
Such problems occur with the drives connected to VIA vt82c686b south
bridge: the same drives on a mvp3 show no such problems.
The behaviour is the same on kernels 2.2.17 & 2.4.3 (both hand
compiled & RedHat's 2.4.2-2 & 2.2.17-14 in case I was doing something
wrong).
The problem is easily demonstrated by hdparm -t. The CPU use jumps to
system 100% as above and all my drives report ~1.9 MB/sec in PIO mode
which is far lower than PIO on the mvp3 (~10MB/s).
DMA mode appears to work fine but I am not using it due to publicised
potential problems.
Regards,
Tom Ford
Thomas Ford wrote:
> Heavy disc writes (eg. unzipping linux kernel source) cause the system
> processor usage (as reported by top/xosview) to jump to 100%, making
> the X mouse/audio freeze etc.
>
> Such problems occur with the drives connected to VIA vt82c686b south
> bridge: the same drives on a mvp3 show no such problems.
>
> The behaviour is the same on kernels 2.2.17 & 2.4.3 (both hand
> compiled & RedHat's 2.4.2-2 & 2.2.17-14 in case I was doing something
> wrong).
>
> The problem is easily demonstrated by hdparm -t. The CPU use jumps to
> system 100% as above and all my drives report ~1.9 MB/sec in PIO mode
> which is far lower than PIO on the mvp3 (~10MB/s).
>
> DMA mode appears to work fine but I am not using it due to publicised
> potential problems.
>
> Regards,
>
> Tom Ford
> -
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Can you share a link to the "publicised potential problems" for DMA mode?
I'm running VIA686A using DMA mode and haven't had any problems.
However, the disk isn't operating as efficiently as I thought it would
(hdparm -t reports 16.3 MB/sec even though I'm using an 80w cable
with an ATA100 drive). I believe that this is due in part to
corrective measures taken by RedHat to fix potential problems with
the VIA chipset; I saw it reported somewhere that the same configuration
will work 20+ MB/sec on distros like Debian).
--
-o) j o h n e w e b e r
/ \ aspiring computer scientist & lover of pengiuns
_\_v
Ignacio Monge wrote:
>
> Hi.
> I have VIA686a too and a UDMA100 hard disk.
So do I.
> This is my cat /proc/ide/via:
>
> ----------VIA BusMastering IDE Configuration----------------
> Driver Version: 3.23
> South Bridge: VIA vt82c686a
> Revision: ISA 0x22 IDE 0x10
> Highest DMA rate: UDMA66
> -------------------drive0----drive1----drive2----drive3-----
> Transfer Mode: DMA UDMA PIO PIO
> Address Setup: 30ns 30ns 120ns 120ns
> Cmd Active: 90ns 90ns 480ns 480ns
> Cmd Recovery: 30ns 30ns 480ns 480ns
> Data Active: 90ns 90ns 330ns 330ns
> Data Recovery: 30ns 30ns 270ns 270ns
> Cycle Time: 120ns 60ns 600ns 600ns
> Transfer Rate: 16.5MB/s 33.0MB/s 3.3MB/s 3.3MB/s
What is odd here is the 33MB/s on drive 1. If it was operating
at UDMA66, that would be more like 66MB/s (see my own /proc/ide/via).
I guess you should try putting a drive on IDEO as master and the
second on IDE1 (which seems empty) as master too.
> As you can see, l use UDMA66 instead UDMA100. I don't know why. Maybe VIA
> vt82c686a doesn't support it? I have answering in this list a days ago about this
> problem. but none seems to have a question.
686a maxes out at UDMA66. 686b does UDMA100.
> Like you, my system goes down when I try to compile so
> mething (I have a 394 Mb of RAM and a 1 Ghz processor).
I'm clueless, my 686a with IBM DTLA works fine (board is
ASUS A7V, kernel 2.4.3, Duron700, 256MB PC133). The new VIA
IDE fixes in the kernel _might_ be the cause, but I'm not sure.
> Although, my hdparm output is this:
> /dev/hde2:
> Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec
> Timing buffered disk reads: 64 MB in 2.44 seconds = 26.23 MB/sec
> and sometime looks better.
>
> I don't know is this is a problem with the VIA kernel driver or not. But the
> system doesn't seem to work fine since 2.4.2 or 2.4.1 kernel. I hope (plz!) this
> problem will be fixed in future.
> Luck.
>
> PS: in cat /proc/ide/via I see "Cable Type: 40w > 40w"... Is it right? I have a 80w cable, not 40.
>
>
I see 80w in mine, maybe your cable is broken... Did you put the blue
end
of the cable on the motherboard ? Also detecting a 40w cable disables
UDMA66 I guess.
Here's my /proc/ide/via :
----------VIA BusMastering IDE Configuration----------------
Driver Version: 3.20
South Bridge: VIA vt82c686a
Revision: ISA 0x22 IDE 0x10
BM-DMA base: 0xd800
PCI clock: 33MHz
Master Read Cycle IRDY: 0ws
Master Write Cycle IRDY: 0ws
BM IDE Status Register Read Retry: yes
Max DRDY Pulse Width: No limit
-----------------------Primary IDE-------Secondary IDE------
Read DMA FIFO flush: yes yes
End Sector FIFO flush: no no
Prefetch Buffer: yes no
Post Write Buffer: yes no
Enabled: yes yes
Simplex only: no no
Cable Type: 80w 40w
-------------------drive0----drive1----drive2----drive3-----
Transfer Mode: UDMA PIO DMA PIO
Address Setup: 30ns 120ns 60ns 120ns
Cmd Active: 90ns 90ns 90ns 90ns
Cmd Recovery: 30ns 30ns 90ns 90ns
Data Active: 90ns 330ns 90ns 330ns
Data Recovery: 30ns 270ns 90ns 270ns
Cycle Time: 30ns 600ns 180ns 600ns
Transfer Rate: 66.0MB/s 3.3MB/s 11.0MB/s 3.3MB/s
Fran?ois Cami
--
All that is gold does not glitter,
Not all those who wander are lost,
The old that is strong does not wither,
Deep roots are not touched by the frost.
>From the ashes a fire shall be woken,
A light from the shadows shall spring,
Renewed shall the blade that was broken,
The crownless again shall be king.
The Riddle of Strider
JRR Tolkien
On Tue, Apr 24, 2001 at 07:19:41PM -0400, Ignacio Monge wrote:
> I have VIA686a too and a UDMA100 hard disk.
> This is my cat /proc/ide/via:
>
> ----------VIA BusMastering IDE Configuration----------------
> Driver Version: 3.23
> South Bridge: VIA vt82c686a
> Revision: ISA 0x22 IDE 0x10
> Highest DMA rate: UDMA66
> BM-DMA base: 0xb800
> PCI clock: 33MHz
> -----------------------Primary IDE-------Secondary IDE------
> Enabled: yes yes
> Cable Type: 40w 40w
> -------------------drive0----drive1----drive2----drive3-----
> Transfer Mode: DMA UDMA PIO PIO
> Address Setup: 30ns 30ns 120ns 120ns
> Cmd Active: 90ns 90ns 480ns 480ns
> Cmd Recovery: 30ns 30ns 480ns 480ns
> Data Active: 90ns 90ns 330ns 330ns
> Data Recovery: 30ns 30ns 270ns 270ns
> Cycle Time: 120ns 60ns 600ns 600ns
> Transfer Rate: 16.5MB/s 33.0MB/s 3.3MB/s 3.3MB/s
>
> As you can see, l use UDMA66 instead UDMA100.
You use UDMA33 dor your second drive and MWDMA16 for your first.
Check your BIOS UDMA enable settings.
> I don't know why. Maybe VIA vt82c686a doesn't support it?
Yes, it supports modes only up to 66 MB/sec.
> I have answering in this list a days ago about this problem. but none seems to have a question. Like you, my system goes down when I try to compile something (I have a 394 Mb of RAM and a 1 Ghz processor).
> Although, my hdparm output is this:
> /dev/hde2:
> Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec
> Timing buffered disk reads: 64 MB in 2.44 seconds = 26.23 MB/sec
> and sometime looks better.
26 megabytes per second is quite surprising in your setup
> I don't know is this is a problem with the VIA kernel driver or not. But the system doesn't seem to work fine since 2.4.2 or 2.4.1 kernel. I hope (plz!) this problem will be fixed in future.
You can disable the VIA driver.
> PS: in cat /proc/ide/via I see "Cable Type: 40w 40w"... Is it right? I have a 80w cable, not 40.
Check your BIOS settings, if you have disabled UDMA in the BIOS, the
driver can't detect the cable. If that doesn't work, use "ide0=ata66"
on the kernel command line.
--
Vojtech Pavlik
SuSE Labs
Hi.
I have VIA686a too and a UDMA100 hard disk.
This is my cat /proc/ide/via:
----------VIA BusMastering IDE Configuration----------------
Driver Version: 3.23
South Bridge: VIA vt82c686a
Revision: ISA 0x22 IDE 0x10
Highest DMA rate: UDMA66
BM-DMA base: 0xb800
PCI clock: 33MHz
Master Read Cycle IRDY: 0ws
Master Write Cycle IRDY: 0ws
BM IDE Status Register Read Retry: yes
Max DRDY Pulse Width: No limit
-----------------------Primary IDE-------Secondary IDE------
Read DMA FIFO flush: yes yes
End Sector FIFO flush: no no
Prefetch Buffer: no no
Post Write Buffer: no no
Enabled: yes yes
Simplex only: no no
Cable Type: 40w 40w
-------------------drive0----drive1----drive2----drive3-----
Transfer Mode: DMA UDMA PIO PIO
Address Setup: 30ns 30ns 120ns 120ns
Cmd Active: 90ns 90ns 480ns 480ns
Cmd Recovery: 30ns 30ns 480ns 480ns
Data Active: 90ns 90ns 330ns 330ns
Data Recovery: 30ns 30ns 270ns 270ns
Cycle Time: 120ns 60ns 600ns 600ns
Transfer Rate: 16.5MB/s 33.0MB/s 3.3MB/s 3.3MB/s
As you can see, l use UDMA66 instead UDMA100. I don't know why. Maybe VIA vt82c686a doesn't support it? I have answering in this list a days ago about this problem. but none seems to have a question. Like you, my system goes down when I try to compile something (I have a 394 Mb of RAM and a 1 Ghz processor).
Although, my hdparm output is this:
/dev/hde2:
Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec
Timing buffered disk reads: 64 MB in 2.44 seconds = 26.23 MB/sec
and sometime looks better.
I don't know is this is a problem with the VIA kernel driver or not. But the system doesn't seem to work fine since 2.4.2 or 2.4.1 kernel. I hope (plz!) this problem will be fixed in future.
Luck.
PS: in cat /proc/ide/via I see "Cable Type: 40w 40w"... Is it right? I have a 80w cable, not 40.