Re: [PATCH][INCOMPLETE] sata_nv: merge ADMA support

["Bill Rugolsky Jr." <brugolsky@telemetry-investments.com>]

On Sat, Mar 18, 2006 at 03:56:28AM -0500, Jeff Garzik wrote:
> OK, can you try the attached sata_nv.c?  Does it perform to the level 
> that yours does?
 
Yes, the results are approximately the same.  Booting from port 0 (sda)
with ADMA enabled still results in timeouts on port 3 (sdc) while
running tars on the RAID1 array on ports 2&3.

ata4: command 0x25 timeout, stat 0x50
ata4: command 0x25 timeout, stat 0x50
(           xterm-3349 |#0): new 355 us maximum-latency wakeup.
(      watchdog/0-4    |#0): new 468 us maximum-latency wakeup.
ata4: command 0x35 timeout, stat 0x50
ata4: command 0x35 timeout, stat 0x50
ata4: command 0x35 timeout, stat 0x50
ata4: command 0x35 timeout, stat 0x50
ata4: command 0x35 timeout, stat 0x50
ata4: command 0x35 timeout, stat 0x50

After a while, syncing the filesystems hangs the sync process, though
the system continues to function, and I can log in on another VC.

The good news: no long latencies from the status inb() during the
period that it is functional! :-p

Booting without ADMA gives the usual stable behavior, with the long
latencies from the status inb().

I was a little disconcerted when I saw this this in the trace with ADMA
disabled,

   tar-21466 0dnh. 3979us : nv_check_hotplug_adma (nv_interrupt)

until I realized that this

        if (!adma_enabled && host_desc->host_type == ADMA)
                host_desc->host_type--;

only alters the outcome of the "host_desc->host_type == ADMA" test, but
still uses the ADMA-based hotplug functions.

   -Bill

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