Re: [PATCH] ide: Fix ATAPI DMA lost irq problem with CDB intr devices

[Albert Lee <albertcc@tw.ibm.com>]

Albert Lee wrote:
> Hi Bart,
> 
>>Albert Lee wrote:
>>
>>
>>>Problem: IDE ATAPI DMA lost irq with CDB intr devices on Intel ICHx
>>>machines.
>>>
>>>This patch clears the INTR and ERROR bits of DMA status before starting
>>>BMDMA to fix the problem.
>>
>>
>>[PATCH] ide-cd: Handle strange interrupt on the Intel ESB2
>>http://lkml.org/lkml/2006/12/4/201
>>
>>The above patch was already merged so it seems that the list
>>of PCI IDs requiring ->atapi_irq_bogon needs to be expanded...
> 
> 
> Instead of adding PCI IDs to the blacklist, could we just unconditionally
> clear the dma_status:INTR in ide_dma_start()?
> 

Sorry I did not read through the ICH7 irq storm problem well.

It seems clearing dma_status:INTR in ide_dma_start() is only good for
  1. Spurious interrupt problem (http://lkml.org/lkml/2006/12/4/201) and
  2. This CDB intr device + ICHx irq lost problem
    (http://www.mail-archive.com/linux-ide@vger.kernel.org/msg02934.html)
But it does not fix
  3. ICH7 native mode irq storm problem (http://lkml.org/lkml/2006/11/15/94).

Maybe we should clearing the INTR in the interrupt handler, no matter it is
DMA/PIO/ATA/ATAPI, just like what libata does.

Will check ide_intr() to see if we can clear the bmdma_status:INTR there.
--
albert