From: Shawn Anastasio <shawn@anastas.io>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org
Cc: Sam Bobroff <sbobroff@linux.ibm.com>,
Alistair Popple <alistair@popple.id.au>,
Oliver O'Halloran <oohall@gmail.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH kernel v3 0/3] powerpc/ioda2: Yet another attempt to allow DMA masks between 32 and 59
Date: Wed, 12 Jun 2019 00:05:31 -0500 [thread overview]
Message-ID: <1e3de274-aec4-6e69-5e37-be15ea888deb@anastas.io> (raw)
In-Reply-To: <deb34b5f-9472-2156-e58d-8dbcb0a38979@anastas.io>
On 6/5/19 11:11 PM, Shawn Anastasio wrote:
> On 5/30/19 2:03 AM, Alexey Kardashevskiy wrote:
>> This is an attempt to allow DMA masks between 32..59 which are not large
>> enough to use either a PHB3 bypass mode or a sketchy bypass. Depending
>> on the max order, up to 40 is usually available.
>>
>>
>> This is based on v5.2-rc2.
>>
>> Please comment. Thanks.
>
> I have tested this patch set with an AMD GPU that's limited to <64bit
> DMA (I believe it's 40 or 42 bit). It successfully allows the card to
> operate without falling back to 32-bit DMA mode as it does without
> the patches.
>
> Relevant kernel log message:
> ```
> [ 0.311211] pci 0033:01 : [PE# 00] Enabling 64-bit DMA bypass
> ```
>
> Tested-by: Shawn Anastasio <shawn@anastas.io>
After a few days of further testing, I've started to run into stability
issues with the patch applied and used with an AMD GPU. Specifically,
the system sometimes spontaneously crashes. Not just EEH errors either,
the whole system shuts down in what looks like a checkstop.
Perhaps some subtle corruption is occurring?
next prev parent reply other threads:[~2019-06-12 5:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 7:03 [PATCH kernel v3 0/3] powerpc/ioda2: Yet another attempt to allow DMA masks between 32 and 59 Alexey Kardashevskiy
2019-05-30 7:03 ` [PATCH kernel v3 1/3] powerpc/iommu: Allow bypass-only for DMA Alexey Kardashevskiy
2019-06-03 2:03 ` David Gibson
2019-05-30 7:03 ` [PATCH kernel v3 2/3] powerpc/powernv/ioda2: Allocate TCE table levels on demand for default DMA window Alexey Kardashevskiy
2019-07-08 7:01 ` alistair
2019-05-30 7:03 ` [PATCH kernel v3 3/3] powerpc/powernv/ioda2: Create bigger default window with 64k IOMMU pages Alexey Kardashevskiy
2019-07-08 7:01 ` alistair
2019-07-09 0:57 ` Alexey Kardashevskiy
2019-06-06 4:11 ` [PATCH kernel v3 0/3] powerpc/ioda2: Yet another attempt to allow DMA masks between 32 and 59 Shawn Anastasio
2019-06-06 7:17 ` Alistair Popple
2019-06-06 12:07 ` Oliver
2019-06-07 1:41 ` Alistair Popple
2019-06-10 5:19 ` Alexey Kardashevskiy
2019-06-12 5:05 ` Shawn Anastasio [this message]
2019-06-12 6:16 ` Oliver O'Halloran
2019-06-12 19:14 ` Shawn Anastasio
2019-06-12 7:07 ` Alexey Kardashevskiy
2019-06-12 19:15 ` Shawn Anastasio
2019-06-18 4:26 ` Shawn Anastasio
2019-06-18 6:39 ` Alexey Kardashevskiy
2019-06-18 7:00 ` Shawn Anastasio
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