From: Ian Arkver <ian.arkver.dev@gmail.com>
To: Philipp Zabel <p.zabel@pengutronix.de>, linux-media@vger.kernel.org
Cc: kernel@pengutronix.de
Subject: Re: [PATCH] [media] coda: disable BWB for all codecs on CODA 960
Date: Wed, 19 Jul 2017 08:16:29 +0100 [thread overview]
Message-ID: <594ed2a7-df43-4fb4-b12c-5b215b618087@gmail.com> (raw)
In-Reply-To: <20170302101952.16917-1-p.zabel@pengutronix.de>
Hi Philipp,
On 02/03/17 10:19, Philipp Zabel wrote:
> I don't know what the BWB unit is, I guess W is for write and one of the
> Bs is for burst. All I know is that there repeatedly have been issues
> with it hanging on certain streams (ENGR00223231, ENGR00293425), with
> various firmware versions, sometimes blocking something related to the
> GDI bus or the GDI AXI adapter. There are some error cases that we don't
> know how to recover from without a reboot. Apparently this unit can be
> disabled by setting bit 12 in the FRAME_MEM_CTRL mailbox register to
> zero, so do that to avoid crashes.
Both those FSL ENGR patches to Android and VPU lib are specific to
decode, with the first being specific to VC1 decode only.
> Side effects are reduced burst lengths when writing out decoded frames
> to memory, so there is an "enable_bwb" module parameter to turn it back
> on.
These side effects are dramatically reducing the VPU throughput during
H.264 encode as well. Prior to this patch I was just about managing to
capture and stream 1080p25 H.264. After this change it fell to about
19fps. Reverting this patch (or presumably using the module param)
restores the frame rate.
Can we at least make this decode specific? The VPU library patches do it
in vpu_DecOpen. I'd guess disabling the BWB any time prior to stream
start would be OK.
It might also be worth adding some sort of /* HACK */ marker, since
disabling the BWB feels very like a hack to me.
Regards,
Ian
next prev parent reply other threads:[~2017-07-19 7:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 10:19 [PATCH] [media] coda: disable BWB for all codecs on CODA 960 Philipp Zabel
2017-07-19 7:16 ` Ian Arkver [this message]
2017-07-19 8:09 ` Philipp Zabel
2017-07-19 9:15 ` Ian Arkver
2017-07-19 9:32 ` Philipp Zabel
2017-07-19 9:37 ` Ian Arkver
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