Re: [BUG?] SIS IDE DMA errors

[Lionel Bouton <Lionel.Bouton@inet6.fr>]

Vojtech Pavlik said the following on 09/26/2003 07:53 PM:

>On Fri, Sep 26, 2003 at 07:27:35PM +0200, M?ns Rullg?rd wrote:
>  
>
>>Vojtech Pavlik <vojtech@suse.cz> writes:
>>
>>    
>>
>>>Actually, it's me who wrote the 961 and 963 support. It works fine for
>>>most people. Did you check you cabling?
>>>      
>>>
>>I'm dealing with a laptop, but I suppose I could wiggle the cables a
>>bit.  I still doubt it's a cable problem, since reading works
>>flawlessly.
>>    
>>
>
>Hmm, that's indeed interesting and it'd point to a driver problem -
>when reading, the drive is dictating the timing, but when writing, it's
>the controllers turn.
>
>So if the controller timing is not correctly programmed, reads function,
>but writes don't.
>
>Can you send me the output of 'lspci -vvxxx' of the IDE device?
>I'll take a look to see if it looks correct.
>
>  
>
>>It appears to me that during heavy IO load, some DMA interrupts get
>>lost, for some reason.
>>    
>>
>
>Well, I've got this feeling that not just IDE interrupts get lost under
>heavy IO load with recent kernels ...
>
>  
>

This could explain some odd reports. Amongst the usual causes like flaky 
hardware, kernel misconfiguration and the likes, I encountered some 
people for which IO-APIC support would throw their data away...

Now I always ask the users to recompile without IO-APIC, this usually 
brings other problems (awful ethernet perfs for one user comes to my 
mind) but tends to solve IDE instability.

Until today, I've not a single report where lspci -vxxx highlighted any 
IDE register misconfiguration, AFAICS your code *is* correct Vojtech.

LB.

-- 
Lionel Bouton - inet6
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