From: Adrian Chadd <adrian@freebsd.org>
To: Peter Oh <peter.oh@eero.com>
Cc: Zhi Chen <zhichen@codeaurora.org>,
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: Tue, 22 Oct 2019 11:24:36 -0700 [thread overview]
Message-ID: <CAJ-VmonXbUQ=Gv9fBbpN+ez25c3Pz+xxLoL67etMdC0Q+bwyXg@mail.gmail.com> (raw)
In-Reply-To: <d6cfd945-7bab-a01d-0157-e0e1802f66e3@eero.com>
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
next prev parent reply other threads:[~2019-10-22 18:24 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 [this message]
2019-10-30 6:04 ` Peter Oh
2019-10-30 6:28 ` zhichen
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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