SiS 5591 requires hw.ata.ata_dma=0 - Why?

Yiorgos Adamopoulos adamo at
Tue Aug 2 08:58:52 PDT 2005

On 2005-07-19, TomaΎ BorΉtnar <tomaz.borstnar at xxxxxxxx> wrote:
> Yiorgos Adamopoulos wrote:
>> According to ata(4) SiS 5591 is supported at its maximum speed.  However, 
>> unless I set hw.ata.ata_dma=0 at /boot/loader.conf.local I get:
>> ad0: READ command timeout tag=0 serv=0 - resetting
>> ata0: resetting devices ..
> broken chipset or bad cable. Nothing new :) old VIA chipsets often neeeded
> such tweaks.

Well, it cannot be a broken cable, since I changed it and I had the same
behavior.  OTOH, installing Linux on the same machine has (almost) the same
result:  The hard disk is started as PIO4 but when switched to UDMA5 it works
(whereas if I try this with atacontrol mode UDMA5 UDMA5) I get ata0: resetting
devices ..

#include <std/disclaimer.h>
#define POWERED_BY ""

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