Re: [PATCH 5/6] video: edid: print debug message on EDID read out error

[Marco Felsch <m.felsch@pengutronix.de>]

Hi Ahmad,

On 22-12-22, Ahmad Fatoum wrote:
> EDID readout errors happen often, e.g. because the HDMI port doesn't
> have a display connected. However, when a monitor is connected, but some
> other error occurs, barebox is silent. Add a debug message with an error
> code for this.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/video/edid.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/edid.c b/drivers/video/edid.c
> index 96489f2a372c..7e6747ccd521 100644
> --- a/drivers/video/edid.c
> +++ b/drivers/video/edid.c
> @@ -847,20 +847,27 @@ edid_do_read_i2c(struct i2c_adapter *adapter, unsigned char *buf,
>  		ret = i2c_transfer(adapter, &msgs[3 - xfers], xfers);
>  	} while (ret != xfers && --retries);
>  
> -	return ret == xfers ? 0 : -1;
> +	if (ret == 0)

When does the i2c_transfer() return 0? According the API documentation
this shouldn't happen and if otherwise is a bug in i2c_transfer().

Regards,
  Marco

> +		ret = -EPROTO;
> +
> +	return ret == xfers ? 0 : ret;
>  }
>  
>  void *edid_read_i2c(struct i2c_adapter *adapter)
>  {
>  	u8 *block;
> +	int ret;
>  
>  	if (!IS_ENABLED(CONFIG_I2C))
>  		return NULL;
>  
>  	block = xmalloc(EDID_LENGTH);
>  
> -	if (edid_do_read_i2c(adapter, block, 0, EDID_LENGTH))
> +	ret = edid_do_read_i2c(adapter, block, 0, EDID_LENGTH);
> +	if (ret) {
> +		dev_dbg(&adapter->dev, "EDID readout failed: %pe\n", ERR_PTR(ret));
>  		goto out;
> +	}
>  
>  	return block;
>  out:
> -- 
> 2.30.2
> 
> 
>