linux-kernel - Re: [PATCH v2 3/4] media: rkvdec: Re-enable H.264 error detection

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Date:   Mon, 26 Dec 2022 18:33:06 -0300
From:   Ezequiel Garcia <ezequiel@...guardiasur.com.ar>
To:     Nicolas Dufresne <nicolas.dufresne@...labora.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        kernel@...labora.com, linux-media@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/4] media: rkvdec: Re-enable H.264 error detection

Hi Nicolas,

I'm still unsure about this patchset.
It sounds like a good approach and a nice
improvement, but I want to make sure I think through it.

Meanwhile, a small comment...

On Fri, Dec 23, 2022 at 02:38:05PM -0500, Nicolas Dufresne wrote:
> This re-enable H.264 error detection, but using the other error mode.
> In that mode, the decoder will skip over the error macro-block or
> slices and complete the decoding. As a side effect, the error status
> is not set in the interrupt status register, and instead errors are
> detected per format. Using this mode workaround the issue that the
> HW get stuck in error state, and allow reporting that some corruption
> may be present in the buffer to userland.
> 
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@...labora.com>
> ---
>  drivers/staging/media/rkvdec/rkvdec-h264.c | 23 +++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/media/rkvdec/rkvdec-h264.c b/drivers/staging/media/rkvdec/rkvdec-h264.c
> index 4fc167b42cf0c..dfe3e235f099a 100644
> --- a/drivers/staging/media/rkvdec/rkvdec-h264.c
> +++ b/drivers/staging/media/rkvdec/rkvdec-h264.c
> @@ -1162,14 +1162,15 @@ static int rkvdec_h264_run(struct rkvdec_ctx *ctx)
>  
>  	schedule_delayed_work(&rkvdec->watchdog_work, msecs_to_jiffies(2000));
>  
> -	writel(0, rkvdec->regs + RKVDEC_REG_STRMD_ERR_EN);
> -	writel(0, rkvdec->regs + RKVDEC_REG_H264_ERR_E);
> +	writel(0xffffffff, rkvdec->regs + RKVDEC_REG_STRMD_ERR_EN);
> +	writel(0xffffffff, rkvdec->regs + RKVDEC_REG_H264_ERR_E);
>  	writel(1, rkvdec->regs + RKVDEC_REG_PREF_LUMA_CACHE_COMMAND);
>  	writel(1, rkvdec->regs + RKVDEC_REG_PREF_CHR_CACHE_COMMAND);
>  
>  	/* Start decoding! */
>  	writel(RKVDEC_INTERRUPT_DEC_E | RKVDEC_CONFIG_DEC_CLK_GATE_E |
> -	       RKVDEC_TIMEOUT_E | RKVDEC_BUF_EMPTY_E,
> +	       RKVDEC_TIMEOUT_E | RKVDEC_BUF_EMPTY_E |
> +	       RKVDEC_H264ORVP9_ERR_MODE,
>  	       rkvdec->regs + RKVDEC_REG_INTERRUPT);
>  
>  	return 0;
> @@ -1183,10 +1184,26 @@ static int rkvdec_h264_try_ctrl(struct rkvdec_ctx *ctx, struct v4l2_ctrl *ctrl)
>  	return 0;
>  }
>  
> +static int rkvdec_h264_check_error_info(struct rkvdec_ctx *ctx)
> +{
> +	struct rkvdec_dev *rkvdec = ctx->dev;
> +	int err;
> +
> +	err = readl(rkvdec->regs + RKVDEC_REG_H264_ERRINFO_NUM);
> +	if (err & RKVDEC_STRMD_DECT_ERR_FLAG) {
> +		pr_debug("Decoded picture have %i/%i slices with errors.\n",

... still uses pr_debug. I would change it so it uses v4l2_dbg,
and can be controlled using the same debug parameter
as you use in patch 4/4.

> +			 RKVDEC_ERR_PKT_NUM(err), RKVDEC_SLICEDEC_NUM(err));
> +		return VB2_BUF_STATE_ERROR;
> +	}
> +
> +	return VB2_BUF_STATE_DONE;
> +}
> +
>  const struct rkvdec_coded_fmt_ops rkvdec_h264_fmt_ops = {
>  	.adjust_fmt = rkvdec_h264_adjust_fmt,
>  	.start = rkvdec_h264_start,
>  	.stop = rkvdec_h264_stop,
>  	.run = rkvdec_h264_run,
>  	.try_ctrl = rkvdec_h264_try_ctrl,
> +	.check_error_info = rkvdec_h264_check_error_info,
>  };
> -- 
> 2.38.1
>