Re: [PATCH 3/5] cciss: Use kernel provided PCI state save and restorefunctions

From: Jens Axboe
Date: Fri Oct 22 2010 - 15:49:45 EST


On 2010-10-22 21:36, Stephen Cameron wrote:
> --- On Fri, 10/22/10, Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx> wrote:
>
>> From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
>> Subject: [PATCH 3/5] cciss: Use kernel provided PCI state save and restore functions
>> To: axboe@xxxxxxxxx
>> Cc: akpm@xxxxxxxxxxxxxxxxxxxx, smcameron@xxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, mike.miller@xxxxxx, thenzl@xxxxxxxxxx
>> Date: Friday, October 22, 2010, 2:21 PM
>> From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
>>
>> and use the doorbell reset method if available (which doesn't
>> lock up the controller if you properly save and restore
>> all the PCI registers that you're supposed to.)
>
>
> This patch, and all these cciss patches in this series, are vs. the jens/for-2.6.37/drivers branch.
>
> One difference I noticed between linux-2.6.36 and jens/for-2.6.37/drivers is that linux-2.6.36 contains this in drivers/block/cciss.c
> in the function cciss_kdump_hard_reset_controller:
>
> /* The doorbell reset seems to cause lockups on some Smart
> * Arrays (e.g. P410, P410i, maybe others). Until this is
> * fixed or at least isolated, avoid the doorbell reset.
> */
> use_doorbell = 0;
>
> This is not present in jens/for-2.6.37/drivers.
>
> That was added to linus tree by me, because I'd noticed we were
> getting controller lockups and subsequent data corruption when
> attempting kdumps using the doorbell reset when (unbeknownst to me at
> the time) the pci state saving and restoring code wasn't quite right.
> So these patches fix the pci state saving and restoring code, so the
> above "use_doorbell = 0" needs to come out when these patches go into
> Linus's tree. But such a patch cannot be made vs. Jens's tree,
> because that code isn't in Jens's tree.

I sent a pull request to Linus earlier today and I know the drivers
branch merges cleanly into -git, so we should be fine.

I'll get this series queued up as well, but it'll be for a later round
early next week. JFYI.

--
Jens Axboe

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