From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0CF0C433FE for ; Wed, 13 Oct 2021 07:05:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9397D61027 for ; Wed, 13 Oct 2021 07:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbhJMHH3 (ORCPT ); Wed, 13 Oct 2021 03:07:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229818AbhJMHH1 (ORCPT ); Wed, 13 Oct 2021 03:07:27 -0400 Received: from mail-lf1-x136.google.com (mail-lf1-x136.google.com [IPv6:2a00:1450:4864:20::136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DA67C061570 for ; Wed, 13 Oct 2021 00:05:24 -0700 (PDT) Received: by mail-lf1-x136.google.com with SMTP id z11so7430547lfj.4 for ; Wed, 13 Oct 2021 00:05:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=PfnVX7fs5mOAIg5g0IqUeD9+3NCJp4mY90XboBsyTc0=; b=PJn70qZ0of/CLO+ZxZI67bYUqZTq5pvu4J69Nxw34dbToC6iLbo2ubHihqjbU+KWvU jT02ga161bl+/F27IiyaK0qLauaVLgIhgN5hOmgGgxjZ+XoUH49428zf2pNFYPHFfaCR bplSjSXtd3xozXnXz7wtrKc5ZFxoqxM+9OoRo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=PfnVX7fs5mOAIg5g0IqUeD9+3NCJp4mY90XboBsyTc0=; b=YKEQfEwuk4vAz3CCg9jSpEoFFVx9p16St9lBhSqy6LJhd3JEAMCWyxm7qVpp9NIkmo HuQ7gv+tDEaSH1sDrhzunV+oS+EPmk4PZd5xT0Wx1jDecj7HQNezeBeUjLMWY4NCc+OJ x0OHV2zSqFV/4N4aIKuQiFTagRtU0jaVyaykO30q6nE+WnzsIeGPk4Kyu1FM0XHfge6v DC0kx+JoE6SRTMHCD3xVRL2165/u8pJ8lJdS3PHoYLcyNnvVlj9KezcsYEkDugajxQqc RC7V16KrwLfGunKWlDn17qg0jXAl1lCsJQUgOCKAB9LED1jKdYpWl9U2yiYxMQisjWGb ezeg== X-Gm-Message-State: AOAM532XNxjdBErDPOfu2H2TW5CL9xRtcF54ueLgIOwx/P/HNmX+l2iL JynZyqttmxTSid1dr6i4E24jaA5FkqROT19WHTjozw== X-Google-Smtp-Source: ABdhPJxYjLoBprzSyIXGzP7xjmn68PtGM7ruxdJkHX33kuYTv8KEpFlP6xZXAhM7paKE8nSoUpMNEuk3fyQqHBpe0pM= X-Received: by 2002:ac2:4e07:: with SMTP id e7mr1074589lfr.308.1634108722948; Wed, 13 Oct 2021 00:05:22 -0700 (PDT) MIME-Version: 1.0 References: <20211008100423.739462-1-wenst@chromium.org> In-Reply-To: From: Chen-Yu Tsai Date: Wed, 13 Oct 2021 15:05:11 +0800 Message-ID: Subject: Re: [PATCH 0/2] media: rkvdec: Align decoder behavior with Hantro and Cedrus To: Nicolas Dufresne Cc: Ezequiel Garcia , Mauro Carvalho Chehab , Linux Media Mailing List , "open list:ARM/Rockchip SoC..." , linux-staging@lists.linux.dev, LKML , Greg Kroah-Hartman , Andrzej Pietrasiewicz Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, Oct 8, 2021 at 11:42 PM Nicolas Dufresne wro= te: > > Hi Chen-Yu, > > thanks for looking into this. > > Le vendredi 08 octobre 2021 =C3=A0 18:04 +0800, Chen-Yu Tsai a =C3=A9crit= : > > Hi everyone, > > > > While working on the rkvdec H.264 decoder for ChromeOS, I noticed some > > behavioral differences compared to Hantro and Cedrus: > > > > 1. The driver always overrides the sizeimage setting given by userspace > > for the output format. This results in insufficient buffer space whe= n > > running the ChromeOS video_decode_accelerator_tests test program, > > likely due to a small initial resolution followed by dynamic > > resolution change. > > > > 2. Doesn't support dynamic resolution change. > > > > This small series fixes both and aligns the behavior with the other two > > stateless decoder drivers. This was tested on the downstream ChromeOS > > 5.10 kernel with ChromeOS. Also compiled tested on mainline but I don't > > have any other RK3399 devices set up to test video stuff, so testing > > would be very much appreciated. > > > > Also, I'm not sure if user applications are required to check the value > > of sizeimage upon S_FMT return. If the value is different or too small, > > what can the application do besides fail? AFAICT it can't split the > > data of one frame (or slice) between different buffers. > > While most software out there just assumes that driver will do it right a= nd > crash when it's not the case, application that do map the buffer to CPU m= ust > read back the fmt structure as the drivers are all fail-safe and will mod= ify > that structure to a set of valid value s for the context. I believe what is happening in Chromium is that the decoder is opened with some default settings, including the smallest viable resolution for the output side, and the buffers allocated accordingly. When dynamic resolution change happens, the decoder does not check if the current buffers are sufficiently sized; it just assumes that they are. And when it starts pushing data into the buffers, it realizes they are too small and fails. The spec also says: Clients are allowed to set the sizeimage field for variable length compressed data flagged with V4L2_FMT_FLAG_COMPRESSED at ioctl VIDIOC_ENUM_FMT, but the driver may ignore it and set the value itself, or it may modify the provided value based on alignment requirements or minimum/maximum size requirements. The spec only guarantees that the buffers are of sufficient size for the resolution configured at the time they were allocated/requested. So I think my first patch is a workaround for a somewhat broken userspace. But it seems the other stateless drivers are providing similar behavior, as I previously mentioned. > As for opposite direction (output vs capture) format being changed, this = should > be documented in the spec, if you find it too unclear or missing for sate= less > codec (I know it's there for stateful but can't remember, would have to r= e-read, > for stateless) let us know. AFAICT the capture side is working OK and to spec. Regards ChenYu > regards, > Nicolas > > > > > Andrzej, I believe the second patch would conflict with your VP9 series= . > > > > > > Regards > > ChenYu > > > > Chen-Yu Tsai (2): > > media: rkvdec: Do not override sizeimage for output format > > media: rkvdec: Support dynamic resolution changes > > > > drivers/staging/media/rkvdec/rkvdec-h264.c | 5 +-- > > drivers/staging/media/rkvdec/rkvdec.c | 40 +++++++++++----------- > > 2 files changed, 23 insertions(+), 22 deletions(-) > > > >