Re: dma pio4 support problems with opti 82C621

From: narancs1@externet.hu
Date: Mon Jul 24 2000 - 14:58:02 EST


Firstly, thanx for the fast answer,

On 24-Jul-2000 Mark Hahn wrote:
>> >Model=FUJITSU M2724TA, FwRev=7029, SerialNo=06016075
>
> 3.42-6.77 MB/s real data rate, up to 16MB/s transfer rate.
> I wouldn't really worry much about performance.
but it is really noisy and slow in my laptop.
This means that it is the fault of what? ide chipset or linux support of it?
>
>> it seems to support DMA and pio mode 4
> dma, of course, is vastly superior.
but I can't turn it on.
If you read the comments in optixxx.c in the kernel source tree, they don't
even mention it.
So somebody should code it. (don't tell "do it yourself", as I can't)

> PIO is a horrible idea because it eats CPU cycles.
ok, so dma support should be added

>> hdparm -t /dev/hda shows 3 mbyte/sec, but in real, it is very slow.
>
> 3 isn't bad for such a low-density, slow disk.
what? you wrote, that they wrote 3.46-16 MB/sec
so why can't I reach it?

>> dma=0 off, turning it on freezes the system
> your bios probably doesn't configure the controller properly.
so it is a bios bug?
you wrote that linux has got nothing to do with bios calls in the mean of
drivers

>> unmaskirq is off, what's this? may i change?
> sure. it removes some of the pain if your system is crippled to use
> only pio.
I'll try it

10x for all!

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