From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:33222 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751581AbdGSHQc (ORCPT ); Wed, 19 Jul 2017 03:16:32 -0400 Received: by mail-wm0-f68.google.com with SMTP id 65so2234913wmf.0 for ; Wed, 19 Jul 2017 00:16:32 -0700 (PDT) Subject: Re: [PATCH] [media] coda: disable BWB for all codecs on CODA 960 To: Philipp Zabel , linux-media@vger.kernel.org Cc: kernel@pengutronix.de References: <20170302101952.16917-1-p.zabel@pengutronix.de> From: Ian Arkver Message-ID: <594ed2a7-df43-4fb4-b12c-5b215b618087@gmail.com> Date: Wed, 19 Jul 2017 08:16:29 +0100 MIME-Version: 1.0 In-Reply-To: <20170302101952.16917-1-p.zabel@pengutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: 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