Re: [libata/sata_sil] Error on startup

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Alex Gonzalez wrote:
> I am seeing a problem with libata and the sata_sil driver. I was
> redirected here from the lkml so I hope it's the correct list for
> this.
>
> I am running a 2.6.21 SMP mips kernel and on some occasions the kernel
> halts on startup. This only happens at boot time, that is, once the
> system is running it never exhibits the problem.
>
> The problem occurs when trying to read the partitions from the SATA
> drive, on the first call to read_dev_sector(). As I understand it, the
> code finishes doing a sync_page() which starts an asynchronous I/O
> operation and sleeps until awaken by an interrupt generated by the
> SATA device.
>
> I have followed the code through until the call to ata_bmdma_start(),
> where it does:
>
> iowrite8(dmactl | ATA_DMA_START, ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
>
> On a working case, the device interrupts and the flow continues. On a
> non working case, there is a delay of 5 or 6 seconds, and then a
> series of calls to sil_freeze(), ata_bmdma_error_handler() and ata_bmdma_stop().
>
> I am about to delve into the ATA specs to try to understand this
>   

   ATA spec. itself won't avail here, it doesn't cover host's DMA 
support. You probably want to read the part concerning "PCI 
Compatibility and PCI-Native Mode Bus Master Adapters" pf this document:

http://www.t13.org/Documents/UploadedDocuments/project/d1510r1-Host-Adapter.pdf

> interaction, but has anybody seen this behavior before? Please CC me
> on replies.
>   

   Generally, DMA timeouts are seen quite frequently...

MBR, Sergei