linux-kernel - Re: [PATCH v1 1/5] media: rkvdec: Disable H.264 error detection

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Date:   Fri, 10 Jun 2022 09:39:19 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Nicolas Dufresne <nicolas.dufresne@...labora.com>
Cc:     linux-media@...r.kernel.org,
        Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        kernel@...labora.com,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        linux-rockchip@...ts.infradead.org, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/5] media: rkvdec: Disable H.264 error detection

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@...labora.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@...omium.org>
Tested-by: Brian Norris <briannorris@...omium.org>