Re: [RFC V2 PATCH 01/11] cxl/mbox: Add debug of hardware error code

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Mon, 10 Oct 2022 15:41:21 -0700
ira.weiny@intel.com wrote:

> From: Ira Weiny <ira.weiny@intel.com>
> 
> If a mailbox command fails the driver always reports ENXIO.  But this
> may not be enough information to understand why the hardware, or in my
> case Qemu, was failing.
> 
> Add a debug print of the error code returned from the hardware.
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Seems very sensible to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/cxl/core/mbox.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index 16176b9278b4..6c4d024ad0e8 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -181,8 +181,11 @@ int cxl_mbox_send_cmd(struct cxl_dev_state *cxlds, u16 opcode, void *in,
>  	if (rc)
>  		return rc;
>  
> -	if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS)
> +	if (mbox_cmd.return_code != CXL_MBOX_CMD_RC_SUCCESS) {
> +		dev_dbg(cxlds->dev, "MB error : %s\n",
> +			cxl_mbox_cmd_rc2str(&mbox_cmd));
>  		return cxl_mbox_cmd_rc2errno(&mbox_cmd);
> +	}
>  
>  	/*
>  	 * Variable sized commands can't be validated and so it's up to the