From: Gary Thomas <gary@mlbassoc•com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: Linux PPC Development <linuxppc-dev@ozlabs•org>
Subject: Re: Change in PCI behaviour
Date: Sat, 04 Dec 2010 05:49:28 -0700 [thread overview]
Message-ID: <4CFA38D8.3060209@mlbassoc.com> (raw)
In-Reply-To: <4CEBD33D.7020603@mlbassoc.com>
On 11/23/2010 07:44 AM, Gary Thomas wrote:
> On 11/22/2010 01:26 PM, Benjamin Herrenschmidt wrote:
>> On Mon, 2010-11-22 at 03:01 -0700, Gary Thomas wrote:
>>> I have a bit more information on this. I'm pretty sure that the failures
>>> are only happening in my SCSI (SATA actually) code. My board (8347ea)
>>> has
>>> a PCI bus with a SIL SATA controller. This combo works perfectly in
>>> 2.6.28.
>>> In 2.6.32, it will run for a while (possibly quite a while), then
>>> timeout
>>> trying to do a large block write - typically 256 blocks. Once this
>>> timeout
>>> happens, the SIL controller is stuck and accesses to it will eventually
>>> cause the whole system to hang (as above).
>>>
>>> Was there any major change in how PCI or DMA was handled between 2.6.28
>>> and 2.6.32? Given the ephemeral nature of these failures (multiple runs
>>> all eventually fail, but never the same twice), my only hope of
>>> fixing it
>>> will be to have some ideas what might have changed.
>>
>> Maybe the changes you did to the PCI outbound windows are now breaking
>> DMA ? Make sure the outbound and inbound don't overlap for example and
>> that all RAM is reachable for inbound.
>
> Here's what I did to work around this - in my DTS, I set up my PCI as
> ranges = <0x02000000 0x0 0xC4000000 0xC4000000 0x0 0x1C000000
> 0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>;
> Before, I had it as
> ranges = <0x02000000 0x0 0xC0000000 0xC0000000 0x0 0x20000000
> 0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>;
>
> I wasn't sure how to reserve the memory (based on your earlier suggestion),
> so I just narrowed the window. Note that I did not change the PCI hardware
> registers (maybe the FSL code does?), so the outbound window should still
> be the whole 512MB.
>
> If this isn't viable, perhaps you could explain a bit more how to reserve
> such a chunk of memory so that the PCI mappings remain the same.
Any ideas on this? I'm a bit lost as to how to reserve the memory like
you suggested and what I've tried so far has met little success.
Thanks again
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
next prev parent reply other threads:[~2010-12-04 12:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-19 15:42 Change in PCI behaviour Gary Thomas
2010-11-19 21:46 ` Benjamin Herrenschmidt
2010-11-21 17:59 ` Gary Thomas
2010-11-22 10:01 ` Gary Thomas
2010-11-22 20:26 ` Benjamin Herrenschmidt
2010-11-23 14:44 ` Gary Thomas
2010-12-04 12:49 ` Gary Thomas [this message]
2010-12-04 21:07 ` Benjamin Herrenschmidt
2010-11-22 10:37 ` Gabriel Paubert
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4CFA38D8.3060209@mlbassoc.com \
--to=gary@mlbassoc$(echo .)com \
--cc=benh@kernel$(echo .)crashing.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox