Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 10 Jun 2022 09:39:19 -0700
From:   Brian Norris <briannorris@chromium.org>
To:     Nicolas Dufresne <nicolas.dufresne@collabora.com>
Cc:     linux-media@vger.kernel.org,
        Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Boris Brezillon <boris.brezillon@collabora.com>,
        kernel@collabora.com,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/5] media: rkvdec: Disable H.264 error detection
Message-ID: <YqNzt9T9BaYu8tgb@google.com>
References: <20220610125215.240539-1-nicolas.dufresne@collabora.com>
 <20220610125215.240539-2-nicolas.dufresne@collabora.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220610125215.240539-2-nicolas.dufresne@collabora.com>
Precedence: bulk

On Fri, Jun 10, 2022 at 08:52:11AM -0400, Nicolas Dufresne wrote:
> Quite often, the HW get stuck in error condition if a stream error
> was detected. As documented, the HW should stop immediately and self
> reset. There is likely a problem or a miss-understanding of the self
> self reset mechanism, as unless we make a long pause, the next command
> will then report an error even if there is no error in it.
> 
> Disabling error detection fixes the issue, and let the decoder continue
> after an error. This patch is safe for backport into older kernels.
> 
> Fixes: cd33c830448b ("media: rkvdec: Add the rkvdec driver")
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

This is effectively how ChromeOS previously was using this hardware for
years. When moving to the upstream/staging driver, this started giving
us problems. This fix is helpful; we'd rather sacrifice error detection
for now, to avoid hanging the hardware in error cases ;)

Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>