From: zhichen@codeaurora.org
To: Adrian Chadd <adrian@freebsd.org>
Cc: Peter Oh <peter.oh@eero.com>, ath10k <ath10k@lists.infradead.org>,
linux-wireless@vger.kernel.org
Subject: Re: [PATCH RFC] Revert "ath10k: fix DMA related firmware crashes on multiple devices"
Date: Wed, 30 Oct 2019 14:28:41 +0800 [thread overview]
Message-ID: <fb2b3b1fc5b3fd00a23e97413777a21e@codeaurora.org> (raw)
In-Reply-To: <CAJ-VmonXbUQ=Gv9fBbpN+ez25c3Pz+xxLoL67etMdC0Q+bwyXg@mail.gmail.com>
On 2019-10-23 02:24, Adrian Chadd wrote:
> On Tue, 22 Oct 2019 at 10:17, Peter Oh <peter.oh@eero.com> wrote:
>>
>>
>> On 10/22/19 1:57 AM, Zhi Chen wrote:
>> > This reverts commit 76d164f582150fd0259ec0fcbc485470bcd8033e.
>> > PCIe hung issue was observed on multiple platforms. The issue was reproduced
>> > when DUT was configured as AP and associated with 50+ STAs.
>> >
>> > With PCIe protocol analyzer, we can see DMA Read crossing 4KB boundary when
>> > issue happened. It broke PCIe spec and caused PCIe stuck.
>>
>> How can you say value 0 (I believe it's 64 bytes) DMA burst size
>> causes
>> the symptom and 1 fixes it?
>
>
> +1 to this question.
>
> Also, shouldn't the DMA engine be doing what the firmware says? Is the
> firmware/copy engine actually somehow bursting / prefetching across a
> 4K page boundary?
>
> Surely this is something that can be fixed in software/firmware by
> correctly configuring up buffer size/offsets?
>
>
>
> -Adrian
DMA engine is working as expected as the configuration. It's copy engine
which actually
splits the RD/WR requests and accesses host memory.
And yes it's platform related configuration. We have never hit this
issue on x86 platform.
Zhi
next prev parent reply other threads:[~2019-10-30 6:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 8:57 [PATCH RFC] Revert "ath10k: fix DMA related firmware crashes on multiple devices" Zhi Chen
2019-10-22 10:07 ` Tom Psyborg
2019-10-30 2:44 ` zhichen
2019-11-06 10:01 ` Tom Psyborg
2019-11-07 5:35 ` zhichen
2019-10-22 17:16 ` Peter Oh
2019-10-22 18:24 ` Adrian Chadd
2019-10-30 6:04 ` Peter Oh
2019-10-30 6:28 ` zhichen [this message]
2019-10-30 6:16 ` zhichen
2019-10-30 23:01 ` Peter Oh
2019-11-03 15:36 ` Tom Psyborg
2019-11-04 18:41 ` Peter Oh
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